knocks
knocks — noun
- knockssingular
- knocksesplural
1. the brief, loud sound that results when one hard object strikes another, or when
the brief, loud sound that results when one hard object strikes another, or when a machine develops a fault.
Three sharp knocks came from the front door, so Ava got up to answer it.
The mechanic listened to the engine and heard a faint knocking sound inside.
knocking sound — typical collocation with mechanical noises
A loud knock on the wooden table made everyone in the room turn around.
Linh heard soft knocks from the pipes every time the heating came on.
- loud knock
- sharp knock
- knocking sound
2. the action of being struck by something hard, often causing pain or damage.
the action of being struck by something hard, often causing pain or damage.
Gabriel received a knock on the head from a falling branch during the storm.
a knock on the [body part] — common physical-hit pattern
The old box suffered several knocks during the move, and its corners were damaged.
Zuri felt a sharp knock on her shoulder when someone pushed past on the bus.
The suitcase took a hard knock at the airport and now the handle is broken.
- hard knock
- sharp knock
- knock on the head
Usage Note
Often used with a body part after 'on': a knock on the head, knee, or shoulder.
3. an unpleasant event or piece of bad luck that delays progress or causes disappoi
an unpleasant event or piece of bad luck that delays progress or causes disappointment.
Failing the exam was a real knock for Lakshmi, who had studied very hard.
The company's loss of a big client was a serious knock to its yearly profits.
For small shops, the rise in rent was yet another knock they could not afford.
The injury was a heavy knock for the athlete just before the Olympic trials.
a heavy knock — setback collocation meaning a serious blow
- heavy knock
- serious knock
- real knock
4. an unkind or unfair critical remark about someone or something.
an unkind or unfair critical remark about someone or something.
The main knock on the new cafe is that the coffee is too expensive.
the main knock on — criticism pattern
Ada takes any knock about her work as a chance to improve, not an insult.
One common knock against the plan is that it costs too much money.
The reviewer's main knock was that the book was too long and boring.
- main knock
- common knock
- praise
positive comments about something
Usage Note
Commonly appears in the phrases 'the main knock on/against' when stating the most frequent criticism.
knocks — verb
- knockspresent simple I / you / we / they
- knockses3rd person singular
- knocksing-ing form
- knocksedpast simple
1. to strike a door, window, or similar surface with your hand or an object in orde
to strike a door, window, or similar surface with your hand or an object in order to get someone's attention.
Lakshmi knocked on the office door and waited for someone to let her in.
knock + on + door — standard transitive pattern
A stranger knocked at the window, so Shirin stayed still and did not move.
The delivery driver knocked loudly, then left the package on the step.
Before you enter the classroom, please knock and wait for the teacher's reply.
Trang knocked on her neighbor's apartment door to ask for a cup of sugar.
- knock on the door
- knock at the window
- knock loudly
Grammar Patterns
knock + on/at + door/window
knock + adv/prep
Usage Note
Requires a preposition (on or at) before the object. 'Knock the door' without a preposition is not correct.
Common Mistakes
2. if a vehicle engine knocks, it produces a series of sharp tapping sounds caused
if a vehicle engine knocks, it produces a series of sharp tapping sounds caused by uneven fuel combustion or a worn component.
Ava's car engine started knocking after she used the wrong type of fuel.
engine + starts knocking — intransitive pattern
The mechanic said the engine was knocking and needed new spark plugs.
If your motorbike engine knocks, you should take it to a garage right away.
The old truck's engine knocked loudly as it struggled up the mountain road.
- engine knocks
- engine is knocking
- pink
British English term for the same engine problem; less common in US English
Grammar Patterns
engine + knocks
engine + is knocking
3. if a pipe, radiator, or similar fixture is knocking, it produces a regular tappi
if a pipe, radiator, or similar fixture is knocking, it produces a regular tapping sound, typically caused by expansion during heating or by trapped air.
Whenever the heating turned on, the pipes in the bathroom began knocking.
pipes + begin knocking — intransitive when heating
The old radiator knocked all night, so Gabriel could not get any sleep.
A plumber fixed the knocking pipes by releasing the trapped air from the system.
The strange knocking sound from the wall worried Isabela, so she called a repair person.
- pipes knock
- radiator knocks
- knocking pipes
Grammar Patterns
pipe + knocks
radiator + knocks
Usage Note
This sense is restricted to plumbing and heating systems; it is not used for general mechanical noises.
4. to strike someone or something hard, especially so that they move, fall, or beco
to strike someone or something hard, especially so that they move, fall, or become damaged.
Mei accidentally knocked her coffee cup off the desk and it shattered on the floor.
knock + object + off — causing something to fall
The strong wind knocked over several bicycles parked outside the library.
Daichi knocked a vase off the shelf with his elbow while reaching for a book.
knock + object + off — accidental striking that causes something to fall
Zuri knocked a pile of books off the shelf while reaching for her phone.
The toddler knocked his glass of milk onto the kitchen floor during dinner.
- knock over
- knock off
- knock down
- knock out
Grammar Patterns
knock + object + off/over/down/out
knock + object + adv/prep
Usage Note
Common patterns include knock + object + off (causing to fall from a surface), knock + object + over (causing to tip), and knock + object + down (causing to fall to the ground).
Common Mistakes
5. to remove part or all of an interior wall to connect two rooms, creating one lar
to remove part or all of an interior wall to connect two rooms, creating one larger space.
The owners decided to knock through the wall between the kitchen and the dining area.
knock through the wall — standard phrasal pattern for wall removal
The family knocked the two spare bedrooms into one large room for the children.
The builders knocked through to make the living room much bigger and brighter.
Isabela and Piotr knocked down the wall to create an open-plan kitchen.
- knock through
- knock into
- knock down
- break through
less common but similar meaning
- open up
broader meaning that can include removing furniture, not just walls
Grammar Patterns
knock + through + room
knock + room + into + room
Usage Note
This sense is most common in British English. American English prefers 'break through' or 'open up' for the same idea.
6. to say unkind or critical things about someone or something, often in a way that
to say unkind or critical things about someone or something, often in a way that is not fair or reasonable.
The critics knocked the film for having a weak plot and poorly developed characters.
knock + object + for + reason — criticism pattern
People are always knocking the city, but Linh thinks it is a lovely place.
The manager knocked the team's performance even though they had tried their hardest.
Some parents knock the new school rules without really understanding the reasons behind them.
- knock someone for something
- knock a plan
- knock a product
- praise
to express approval or admiration
Grammar Patterns
knock + object + for + reason
knock + object (person/thing)
Usage Note
Informal register. In formal or academic writing, prefer criticize, find fault with, or disparage.
Common Mistakes
Word family
Synonym discussion
Sense: verb/1
All four words describe striking a surface, but they differ in force, purpose, and sound. Knock is the most neutral and common term — you knock on a door to announce your arrival, using a closed fist or knuckles with moderate force. Tap is much lighter and quieter, often using the fingertips or an object held delicately, like tapping a keyboard or tapping someone on the shoulder. Rap is sharper and more urgent than a knock, suggesting impatience or insistence; you might rap on a table to get a room's attention. Bang is the strongest, implying loud, forceful, or angry striking, such as banging a fist on a door when no one answers. In everyday conversation, knock covers most situations. Tap is for gentleness, rap for urgency, and bang for anger or alarm.
Common collocations
Etymology
Knock comes from the Old English verb cnocian, meaning to strike hard. It is related to similar words in Old Norse (knoka) and Old High German (chnohhan). The word is believed to be imitative in origin — that is, it was created to sound like the noise it describes. The meaning 'to criticize' developed in American English in the late 1800s, and the noun sense meaning a setback or misfortune appeared around the same period.
First known use
12th century
12th century, in the meaning defined at intransitive sense 1 Noun