The Phrasal Verb 'Knock Out' Explained
- Phrasal Verbs Explained
- Jul 4
- 13 min read
An explanation of the different meanings of the English phrasal verb 'knock out' from a native speaker, with lots of examples in context
Hello and welcome to my website for English learners all about phrasal verbs where I explain their different meanings to help you understand, learn and use them like a native.
'Knock out' is an English phrasal verb that you may recognise if you watch combat sports like boxing or MMA. Did you know however that there are at least 7 different ways to use it? In this post, I will explain all of these different meanings for you, as well as some additional uses that 'knock out' has. Additionally, I will provide you with lots of example sentences so that you understand the types of contexts and situations in which we use them. So, without further ado, let's make a start....
TABLE OF CONTENTS (Click to jump to each one)
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THE BASICS
KNOCK OUT: KEY INFORMATION
Usage | Common |
Number of meanings | 7 |
Past tense forms | Knocked out / Knocked out |
Separable? | Yes |
To begin, let's briefly look at the verb 'to knock' and the particle 'out' separately in order to gain some useful background information on our chosen phrasal verb.
'To knock' is a relatively common English verb, which I am sure that many of you will be familiar with already. We use it primarily to talk about hitting or striking something, often to make a noise or to make something move from the position that it is in. In some contexts, it can be used to mean 'to collide lightly with something', often when little or no damage is caused.
I knocked your door but you didn't answer.
Please knock before entering!
The builder knocked the ornament with his ladder and it fell over.
John knocked his head on the low ceiling.
I accidentally knocked the fence post as I was reversing but I don't think any damage was done.
'Out' is a prepositional particle that is frequently found in phrasal verb constructions. As you probably know, it is primarily used to talk about being on or moving towards the external part of something and it's natural linguistic opposite is the word 'in'. This external idea of 'out' is one that can also be found in phrasal verbs (go out, get out), however there are many other functions that 'out' can bring to phrasal verbs and these include emergence (come out), removal (take out) and ending (die out). Moreover, sometimes 'out' can be used in phrasal verbs to signify a shift from active to inactive, as we will see shortly.
So, now that we have covered the basics, let's move on to the different meanings of the phrasal verb 'knock out'....
MEANING 1: Literal
CEFR Language Level | A2 - Elementary |
Usage | Medium |
Where is it used? | Everywhere |
Potential synonyms | To dislodge, to remove, to extract |
Separable? | Yes |
Did you know that the phrasal verb 'knock out' is used in a literal sense by native speakers?This is typically to refer to when something is removed from somewhere by hitting, striking or bumping it.
Nouns commonly used with this application....
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For this application of 'knock out', you should know that we only use it to talk about objects that are physically embedded or fixed in a larger structure or object.
Typical examples of this would be if someone hits you and knocks one of your teeth out (teeth are embedded in the mouth) or if a builder knocks a wall out in a house (a wall is an integral part of a house).
This literal action of 'knocking out' can be done either intentionally or accidentally; the key idea is that something is dislodged or removed by force.
The mechanic had to knock out the broken window pane before replacing it.
When I fell over, I knocked a tooth out and now I have a gap in my smile.
Peter knocked out the nails holding the old shelf in place and it fell to the floor.
We decided to knock out the wall between the kitchen and living room to make the room bigger.
Lou knocked out a brick in the wall to create a space for the wiring.
MEANING 2: To make someone unconscious
CEFR Language Level | B2 - Upper intermediate |
Usage | Common |
Where is it used? | Everywhere |
Potential synonyms | To make / render unconscious |
Separable? | Yes |
If you are a fan of boxing or other combat sports, it is likely that you will already be familiar with our next application of 'knock out' as it means 'to make someone unconscious, normally by a strike to the head'.
Of course, this usage is not only applicable in the world of sports and it can be used to describe any occasion on which you receive a blow to the head that makes you lose consciousness for a period of time. This may be from another person if they hit you or it may be from an inanimate object if that somehow makes contact with your head; in the second case it is possible to say that you "knock yourself out" if the head impact was a result of your own movement or actions e.g, you hit your head on a low ceiling.
Sometimes, we add the additional word 'cold' after 'knocked out' to stress that a person was completely unconscious after being struck.
The boxer knocked out his opponent in the third round.
The fall was so bad it nearly knocked John out cold.
Sally was knocked out during the accident and didn’t remember anything afterwards.
Marcus hit his head on the beam and it knocked him out instantly.
One punch from the fighter was enough to knock out the challenger.
I should mention here that in boxing or other types of fighting sports, 'knock out' doesn't necessarily mean that the fighter is unconscious. It simply means that they are on the floor for a period of 10 seconds and can no longer participate in the fight...more about this later. |
TO MAKE UNCONSCIOUS OR TO MAKE SOMEONE FALL ASLEEP?
Did you know that English speakers also use the word 'unconscious' in an informal way to mean deeply asleep (a bit like the cat above), even though we are not technically unconscious in the true sense of the word. As a result of this, the usage of 'knock out' has developed over time to also include when we take drugs or drink alcohol which cause us to fall deeply asleep.
For example, you may be knocked out by drinking too much wine or if you are having trouble sleeping, you may take sleeping tablets to knock you out.
Of course, this meaning is also applied to talk about when you are rendered truly unconscious by anaesthetic to undergo an operation in hospital.
The anaesthetic will knock you out before the surgery starts.
The gas leak could knock out anyone who breathes it in for too long.
That sleeping pill really knocked me out; I was out cold for ten hours straight.
Be careful with that cough syrup; it can knock you out if you take too much.
The sedative was strong enough to knock out a horse.
MEANING 3: To eliminate a competitor
CEFR Language Level | B2 - Upper intermediate |
Usage | Common |
Where is it used? | Everywhere |
Potential synonyms | To eliminate, to defeat |
Separable? | Yes |
Earlier on in the post, I explained how 'knock out' can be used to talk about combative sports like boxing when a fighter is hit and becomes unconscious. For this third application of 'knock out' we are again returning to the world of sport as this next meaning is 'to eliminate a competitor from a competition'.
Nouns commonly used with this application....
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Firstly, it is important to note that we only use this application to talk about knockout competitions; i.e. the competitions where there are progressive rounds with semi-finals and a final at the end, like the football World Cup or Wimbledon. If a person or team is knocked out of one of these competitions, it means that they are defeated and therefore cannot progress to the next round and are therefore out of the competition.
As I said, you will typically hear this being used to refer to sports tournaments but it is also widespread in all types of knockout competitions, especially those on the television.
On a grammatical level, this application can be used both separably and inseparably. Furthermore, it is also possible to use it in both the active and passive voice using the passive variations 'be knocked out' and 'get knocked out'.
The Spanish team was knocked out of the tournament in the quarter-finals.
We were sadly knocked out in the first round after a tough match.
The British tennis mixed double duo got knocked out by the defending champions.
The chess player's loss in the semifinals knocked her out of the title race.
The underdog team managed to knock out last year's winners in a surprise turn of events.
MEANING 4: To disable equipment
CEFR Language Level | C1 - Advanced |
Usage | Medium |
Where is it used? | Everywhere |
Potential synonyms | To disable, to destroy, to damage |
Separable? | Yes |
Our fourth meaning of 'knock out' is one that is often heard in connection with warfare and destruction and means 'to disable equipment'.
Nouns commonly used with this application....
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To begin, let me clarify by saying that when I say 'to disable' it means 'to stop from functioning or being effective'. This is usually as the result of damage, which can be either physical with machines and equipment or non-physical such as IT infrastructures and websites.
As I mentioned earlier, you will hear this commonly being applied in reference to war and hostile human interaction since it is possible for both physical equipment and systems like electricity or gas supply networks to be knocked out by aggressive military attacks.
Moreover, it is also used when talking about damage that arises from natural causes, like lightning, fire and flooding, which all also have the ability to stop things from functioning.
The lightning strike knocked out power in the radio tower.
The bomb blast knocked out several surveillance cameras.
Construction accidentally knocked out the water supply to the neighbourhood.
A falling tree knocked out the telephone lines.
The fire knocked out the building’s emergency lighting.
The storm knocked out the electricity supply to thousands of homes.
The explosion knocked out the communication system.
The other area that we use this application of 'knock out' more and more in today's world is with reference to IT and computer systems. If anything happens to disable an IT system or stop a computer or network of computers from working, we can use 'knock out' to describe this. Likewise, it is also possible to use it for technical and electrical faults that prevent something from working correctly.
A power surge knocked out all the computers in the office.
The virus knocked out the hospital's internal network.
The update bug knocked out users' access to the app.
A malware attack has knocked our main server out and technicians are working on a solution.
A technical fault knocked out the entire air conditioning system on the hottest day of the year.
A group of hackers managed to knock out the company’s website for several hours yesterday.
MEANING 5: To astonish someone
CEFR Language Level | C1 - Advanced |
Usage | Medium |
Where is it used? | Everywhere |
Potential synonyms | To impress, to astonish, to overwhelm |
Separable? | Yes |
Our fifth meaning of 'knock out' is not as common as some of the others that we have looked at so far and means 'to astonish someone'.
Firstly, if you are not familiar with the verb 'to astonish', it means 'to greatly impress or to surprise someone'. If something knocks you out in this sense, it means that it shocks you, usually in a positive way.
As you can imagine, we only tend to use this application of 'knock out' for those rare, exceptional moments in our lives when we feel extremely impressed, surprised or emotionally moved by something.
This usage is quite an informal one and therefore is mostly used in casual conversations and song lyrics.
The performance really knocked me out; it was incredibly beautiful.
Your new song just knocked me out. I’ve had it on repeat all day.
Emily walked into the room in her wedding dress and completely knocked everyone out.
Sebastian's talent for painting absolutely knocked me out.
The view from the mountaintop just knocked us out; we weren’t expecting it to be that breathtaking.
The chef’s tasting menu knocked them out; every dish was a masterpiece.
MEANING 6: To produce something quickly or effortlessly
CEFR Language Level | C1 - Advanced |
Usage | Medium |
Where is it used? | Everywhere |
Potential synonyms | To produce, to manufacture, to turn out, to knock up |
Separable? | Yes |
Our sixth application of 'knock out' is one that can be used informally to talk about businesses and services and means 'to produce something quickly or effortlessly'.
Nouns commonly used with this application....
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When working in the same job or doing the same thing for work for a long time, most people reach a stage where they can do many aspects of their job role quickly, often without concentrating very hard on it. In instances such as these it is possible to use this application of 'knock out'.
To explain further, this application of 'knock out' is commonly used when we easily or uickly generate or produce something through effort. This could be a report, a presentation, or a manufactured item - it doesn't matter what; the key point is that something was created in the process.
Moreover, with this application there is usually a remarkable aspect to the work, like producing a large quantity of products or something that takes a lot of skill and expertise in a short period of time. As such, we often state the time period in which the product or service was 'knocked out' in the sentence.
Laura knocked out a ten-page report in just a few hours.
Tony can knock out a song in one afternoon when he's inspired.
The team hastily knocked out the presentation the night before the meeting.
I’ll try to knock out a rough draft before lunch and send it to you.
The artist knocked out three sketches during the afternoon break.
We knocked out the design mockups over the weekend.
Paul’s so efficient, he can knock out emails while on a call.
MEANING 7: To earn money
CEFR Language Level | C1 - Advanced |
Usage | Medium |
Where is it used? | Australian English |
Potential synonyms | To earn, to obtain |
Separable? | Yes |
The last of the meanings of the phrasal verb 'knock out' that we will cover in this post is an Australian usage which means 'to earn money'.
This application is typically used to talk about when someone makes money in a casual or unexpected way and is very informal in nature.
More rarely, it can also be used to talk about obtaining food from somewhere.
From a British English speaker's perspective (mine), this one is quite unknown and although I would be able to understand what it meant from the context most of the time, it might not always be clear, so be careful if using this one with any speakers of English that are not Australasian.
Steve knocked out a few hundred bucks doing weekend shifts at the pub.
Delilah’s been knocking out decent money with her freelance gigs.
You can knock out good cash during harvest season if you’re willing to work hard.
Martine and Frankie knocked out a bit of extra income selling stuff online.
THE NOUN 'KNOCKOUT'
In addition to the phrasal verb, we also have the noun 'knockout' in English which has a couple of meanings; both of which are to do with sport and are derived from the meanings of the phrasal verbs that we covered earlier in the post.
The first one links back to the second meaning that we covered where people are made unconscious in a fight. A 'knockout' is the noun for this action and is often shortened to the common abbreviation 'KO'. This applies to both when someone is really knocked unconscious and when they remain conscious but are unable to get up off the floor for a count of 10.
The boxer won by a knockout in the second round.
It was a clean knockout, Joe hit the mat and didn’t get back up.
The referee decided to stop the fight after the brutal knockout.
Lastly, if you think back to the third application meaning 'to eliminate a competitor', you may have noticed that I talked about "a knockout competition". A knockout can be used in this sense as a noun to name this type of competition in which competitors are eliminated in rounds all the way to the final at the end. In some cases, such as the football World Cup, there is a knockout stage for the final 16 teams following the initial group stage.
In a knockout competition, there is absolutely no room for error.
The Welsh team made it to the knockout stage after finishing second in their group.
This year’s cup is a straight knockout; there are no second chances.
KNOCK YOURSELF OUT!
Last but not least, if an English speaker ever tells you to "knock yourself out", please do not be offended or worried. They are not telling you to physically harm yourself (as in application 2). Surprisingly, what they are in fact telling you is to 'go ahead do what you want'. This is usually said after someone asks for permission to do something and instead of saying "yes", you can say "knock yourself out", which is a bit stronger and encouraging than a simple "yes". Occasionally, "knock yourself out" can carry slightly sarcastic tones but you can normally pick up on that from the way that the person says it.
If you want to reorganise the garage on your day off, knock yourself out.
Want to try all five flavours of the whisky? Knock yourself out!
You think you can fix the car without reading the manual? Knock yourself out!
We have now reached the end of this post and I just want to say thank you for clicking on my post and reading it. I hope that you've enjoyed it and have been able to learn something new about the phrasal verb 'knock out'. If you enjoyed this post, please go ahead and check out some of my other posts.
Now it is YOUR turn. Can you think of a sentence yourself using 'knock out'. Write it in the comments section below if you can, or alternatively any comments, suggestions or feedback that you may have....don't be shy!!!
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THE END
An admirably exhaustive explanation.
Much valued and much appreciated effort, shortly speaking.
i must knock out insightful and informative writing to knock out my competitors in the market then when they get angry, i will also knock out their websites and systems after that they need new pills to knock them out for sleeping but there is still opportunity, they must knock themselves out to improve their business again.