Meaning & use
knock
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Meanings
verbintransitive
To hit a door or other surface with your hand or an object to make a noise and attract attention.
Grammar: No object; often followed by 'on' or 'at': knock on the door, knock at the window.
Patterns
- knock on something
- knock at something
- knock loudly
Please knock before you come in.
Someone knocked on the door at midnight.
She knocked twice and waited.
verbtransitive
To hit something hard, often causing it to move or fall.
Grammar: Takes an object: knock the glass over, knock the ball into the net.
Patterns
- knock something over
- knock something off something
- knock someone down
He knocked the cup off the table.
The wind knocked a branch onto the car.
She knocked the ball into the goal.
verbtransitiveinformal
To criticize someone or something, especially in an unkind or unfair way.
Grammar: Takes an object; common in the phrase 'don't knock it'.
Patterns
- knock someone
- knock something
- don't knock it
Don't knock the idea until you've tried it.
Critics knocked the film, but audiences loved it.
nouncountable
A sharp blow or the noise made by hitting something, especially a door.
Grammar: Countable: a knock, two knocks, a loud knock.
Patterns
- a knock at the door
- a knock on the head
- hear a knock
There was a loud knock at the door.
He took a knock on the head during the game.
I heard three knocks on the window.
nouncountable
A bad experience or problem that sets someone back.
Grammar: Often used in the phrase 'take a knock'; usually singular.
Patterns
- take a knock
- a knock to something
Her confidence took a knock after the interview.
The company took a knock when sales fell.
Word forms
| third person singular | knocks |
|---|---|
| past tense | knocked |
| past participle | knocked |
| -ing form | knocking |
| plural | knocks |
Common combinations
- knock on the door
- He knocked on the door and waited.
- knock something over
- Be careful not to knock the vase over.
- knock at the window
- She knocked at the window to get my attention.
- a knock at the door
- A sudden knock at the door made us jump.
- knock it off
- Knock it off, you two — stop arguing.
Synonyms and how they differ
- tap
- Tap means to hit lightly and quickly, often to make a soft sound, while knock is usually louder and firmer.
- bang
- Bang suggests a very loud, heavy hit; knock is more controlled and often used for doors.
- rap
- Rap means to knock quickly and sharply, often several times; it sounds more literary or formal than knock.
Word family
Commonly confused: knock or nock? knock or knock out?
knock vs nock
Nock is a rare word for the notch at the end of an arrow; it sounds the same as knock but is unrelated.
knock vs knock out
This phrasal verb means to make someone unconscious or to impress someone greatly, which is stronger than the simple verb knock.
Practice
Which sentence uses the correct preposition with 'knock'?
Choose one answer.
We knock at or on a door, so option 1 is correct. The other prepositions do not fit this meaning.
Make it your own
Write a sentence using “knock”, then check it and compare it with the examples above.