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to knock

to knock

16 8.1
To make a sharp metal sound in an engine when the fuel burns too early
  • verb
  • /nɑk/
  • Specialized
translation icon : detonar
  • The mechanic explained that the unusual knock in the engine was due to premature ignition.

He he added Tetra ethyl lead the scamp as patron discovered it reduced knocking on heaven's door.

Examples

  • I felt like I'd had all the wind knocked out of me.

    Fiction book (1997)
  • So lead was added to fuel to to make engines more efficient, to knock less and to to make them less prone to breakdown.

  • Suddenly, the engine starts knocking violently and the car dies.

    Fiction book (1994)
  • If overdone, hard playing will knock the pans out of tune.

    Academic text (1995)
  • The lifters knock louder as she eases off the gas, rolling into Wild Horse.

    Fiction book (1999)
  • Using higher quality fuel can help reduce engine knock and improve performance.

  • If your car starts to knock, it may be an indication that you need to check the fuel mixture.

Synonyms

to ping
vsto knock
  • Specialized
7.6

To make a metallic knocking sound in an engine when fuel burns too early

specifies a sharp metallic sound from early or irregular ignition inside a cylinder
to pink
vsto knock
  • Specialized
9.9

To make a knocking sound in an engine when fuel burns too early

means a sharp metallic sound rather than a general rattle

Idioms

3 7.6

Make someone feel less proud by criticizing or embarrassing them

1 8.7

To surprise someone very much and leave them speechless

To be so surprised that you almost cannot react

To make someone feel very tired, weak, or sad

1 7.9

To defeat the person or team at the top and take their place

To hit or shock someone so they feel dazed

To sell a lot of movie tickets

To be hit so hard that you fall and cannot get up

knock on wood
  • Informal
6.8

You say it to avoid bad luck after saying something good

To hit someone very hard or to shock someone very much

Phrasal Verbs

to knock it off
  • Informal
321 8.1

Tell someone to stop doing something annoying

210 4.3

To make someone unconscious by a hit, illness, or being very tired

93 3.0

Use force to make someone or something fall to the ground

To hit a door with your hand to get people inside to notice

68 2.6

Make something fall by hitting or bumping it

64 3.8

To break or remove something by force, often by hitting it

57 3.2

Make a building or wall fall down suddenly

46 3.4

To remove someone or something from a competition by defeating them

35 9.9

To make a woman pregnant

19 9.9

Kill someone as part of a crime

to knock out
  • Informal
18 4.7

To impress someone strongly so they feel admiration

15 9.9

To make someone pregnant, said informally

12 4.3

Lower the price by a set amount

To make someone unconscious by hitting them

to knock off
  • Slang
7 8.4

Steal things, for example electronics or cars

Make the electricity go off by damaging power lines or equipment

5 8.1

To make someone start thinking and behaving reasonably, often by scolding or force

to knock boots
  • Offensive
4 9.9

An informal way to say to have sex with someone

to knock off
  • Informal
4 7.4

Stop doing something, often when it is annoying

to knock off
  • Informal
4 6.1

Make something quickly with little effort

Hit something by accident when you move and touch it

to knock down
  • Specialized
1 7.8

Reduce how much a gene works in cells

To surprise someone very much so they cannot react

1 6.7

To make something quickly and simply from things you have, like a shelter or meal

1 6.3

To hit something hard so it moves or gets damaged

Make something quickly that will not last long

To still be around in a place or situation

To appear as a good chance for you

To impress many people by doing something very well

Compounds

knock on
  • Jargon
7 8.2

The illegal action of hitting the ball forward with the hand or arm while trying to catch it

2 4.7

An indirect result of an event that causes other changes

knock knock
  • Informal
2 4.3

A short joke that starts with 'Knock knock!' and uses a call and answer

1 8.4

With knees that bend inward and touch while the ankles stay apart

knock rummy
  • Jargon
1 8.7

A rummy game where a player ends a round if unmatched cards total less than ten points

Very violent and intense, often about a fight or argument

Knees that turn inward and touch when the legs are straight

9.8

A strong feeling or sound in the stomach that tells you to eat soon

How Severe

detonation
  • Specialized
85 6.7
to knock
  • Specialized
16 8.1
to ping
  • Specialized
7.6

Surface Forms

knock infinitive
knocked past
knocked past participle
knocking present participle
knocks third person singular

Etymology

Knock for an engine sound is also from the same simple idea — the engine makes a sharp, knocking noise, so mechanics call that problem 'knock' or 'knocking'.