1 crack /ˈkræk/ verb
cracks; cracked; cracking
1 crack
cracks; cracked; cracking
Learner's definition of CRACK
: to break (something) so that there are lines in its surface but it is usually not separated into pieces
[+ object]
[no object]
[+ object] : to hit or press (something) so hard that it breaks apart or opens suddenly
[+ object] : to hit (someone or something) hard and usually suddenly
[+ object]
: to open (a bottle or can) for drinking usually + open
: to open (a book) for studying or reading
usually + open
[+ object] : to open (a safe) illegally without having a key, combination, etc.
[+ object]
: to find an answer or solution to (something)
: to find the meaning of (a secret code)
[+ object] : to open (something, such as a door or window) a small amount usually + open
: to cause (something) to make a sudden loud sound
[+ object]
[no object]
see also crack the whip (below)
[no object] of a voice : to change sharply in tone or pitch especially because of strong emotion
[+ object] informal : to tell (a joke)
[no object] : to lose strength or the ability to resist or fight
often + under

a tough/hard nut to crack

see nut

crack a smile

: to smile

crack down

[phrasal verb]
: to start to be strict about punishing people for doing something that is illegal or not allowed : to enforce a law or rule more strictly
often + on
see also crackdown

crack into

[phrasal verb]
crack into (something) informal
: to enter or get started in (something, such as a profession)

crack the whip

: to force people to work very hard

crack up

[phrasal verb] informal
crack up or crack (someone) up or crack up (someone) : to begin laughing or cause (someone) to begin laughing suddenly and in a way that is difficult to control
: to become mentally ill : to lose control of your thoughts and emotions so that you cannot continue to live in a normal way
crack up or crack up (something) also crack (something) up US, informal : to damage (a vehicle) by crashing
see also crack-up
◊ Something that is what/all/everything (etc.) it's cracked up to be is as good as people say it is.
◊ This phrase is usually used in negative statements.

crack wise

US, informal
: to say something that is funny and smart : to make a wisecrack

get cracking

: to start doing something
2 crack /ˈkræk/ noun
plural cracks
2 crack
plural cracks
Learner's definition of CRACK
[count] : a thin line in the surface of something that is broken but not separated into pieces
often + in
see also crack in someone's or something's armor at armor
[count] : a very narrow space or opening between two things or two parts of something
[count] : a sudden loud, sharp sound usually singular
[count] : a brief change in the sound of a person's voice especially because of strong emotion usually singular
[count] : a weakness or problem often + in
[count] informal : a joke or rude remark often + about
[count] : a hard and sudden hit usually singular
[count] informal : an effort or attempt to do something usually + at
[noncount] : an illegal drug that is a form of cocaine
called also crack cocaine

a fair crack of the whip

British, informal
◊ If you are given a fair crack of the whip, you are given the same chance as other people to do something.

at the crack of dawn

: very early in the morning : at dawn

fall through/between the cracks

also slip through/between the cracks
: to fail to be noticed or included with others
3 crack /ˈkræk/ adjective
3 crack
Learner's definition of CRACK
always used before a noun
: very good : of excellent quality or ability