1crack 
/ˈkræk/ verb
cracks; cracked; crack·ing /ˈkræk/ verb 1 : to break (something) so that there are lines in its surface but it is usually not separated into pieces [+ obj] ▪ The hailstones were big enough to crack some windows. ▪ He cracked his collarbone in a skiing accident. [no obj] ▪ The mirror/glass cracked when she dropped it. ▪ A piece of the statue cracked off. [=broke off] 2 [+ obj] : to hit or press (something) so hard that it breaks apart or opens suddenly
▪ Workers cracked the large rock into three pieces so it could be moved. ▪ The bird cracked the seed on a tree branch. ▪ a tool used for cracking nuts ▪ He cracked open the eggs. 3 [+ obj] : to hit (someone or something) hard and usually suddenly
▪ Someone cracked him over the head with a beer bottle. ▪ The baby cracked her chin pretty hard when she fell. ▪ He fell and cracked his elbow on/against the ice. 4 [+ obj] a : to open (a bottle or can) for drinking — usually + open ▪ He cracked open a beer.
b : to open (a book) for studying or reading
▪ He hardly cracked a book his whole first semester of college. — usually + open ▪ It's a perfect day to relax and crack open a good book. 5 [+ obj] : to open (a safe) illegally without having a key, combination, etc.
▪ Any good thief could crack this safe. 6 [+ obj] a : to find an answer or solution to (something)
▪ Scientists have cracked [=solved] an ancient mystery using new technology. ▪ The police finally cracked [=broke] the case and arrested the murderer.
b : to find the meaning of (a secret code)
▪ He was able to crack [=break] the enemy's secret code. 7 [+ obj] : to open (something, such as a door or window) a small amount — usually + open ▪ She cracked open the door and peeked into the room. 8 : to cause (something) to make a sudden loud sound [+ obj] ▪ When the sled dogs heard her crack the whip, they broke into a run. ▪ His habit of cracking his knuckles bothered her. [no obj] ▪ The sled dogs are trained to run when they hear the whip crack. — see also crack the whip (below) 9 [no obj] of a voice : to change sharply in tone or pitch especially because of strong emotion
▪ Her voice cracked (with emotion) as she told them what had happened. 10 [+ obj] informal : to tell (a joke)
▪ The two of them crack jokes all the time. = The two of them are always cracking jokes. 11 [no obj] : to lose strength or the ability to resist or fight
▪ After hours of questioning by the police, the suspect finally cracked. [=finally told the police what they wanted to know] — often + under ▪ He cracked under the pressure/stress of the job.
▪ Workers cracked the large rock into three pieces so it could be moved. ▪ The bird cracked the seed on a tree branch. ▪ a tool used for cracking nuts ▪ He cracked open the eggs.
▪ Someone cracked him over the head with a beer bottle. ▪ The baby cracked her chin pretty hard when she fell. ▪ He fell and cracked his elbow on/against the ice.
b : to open (a book) for studying or reading
▪ He hardly cracked a book his whole first semester of college. — usually + open ▪ It's a perfect day to relax and crack open a good book.
▪ Any good thief could crack this safe.
▪ Scientists have cracked [=solved] an ancient mystery using new technology. ▪ The police finally cracked [=broke] the case and arrested the murderer.
b : to find the meaning of (a secret code)
▪ He was able to crack [=break] the enemy's secret code.
▪ Her voice cracked (with emotion) as she told them what had happened.
▪ The two of them crack jokes all the time. = The two of them are always cracking jokes.
▪ After hours of questioning by the police, the suspect finally cracked. [=finally told the police what they wanted to know] — often + under ▪ He cracked under the pressure/stress of the job.
a tough/hard nut to crack — see nut
crack a smile
: to smile
▪ I tried to get him to laugh, but he never even cracked a smile.
▪ I tried to get him to laugh, but he never even cracked a 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
▪ People have been violating this law for years, and now the government is finally starting to crack down. — often + on ▪ Authorities are cracking down on companies that pollute. — see also crackdown
▪ People have been violating this law for years, and now the government is finally starting to crack down. — often + on ▪ Authorities are cracking down on companies that pollute. — see also crackdown
crack into [phrasal verb]
crack into (something) informal : to enter or get started in (something, such as a profession)
▪ Its not easy to crack into [=break into] professional football.
▪ Its not easy to crack into [=break into] professional football.
crack the whip
: to force people to work very hard
▪ The team needs a coach who isn't afraid to crack the whip.
▪ The team needs a coach who isn't afraid to crack the whip.
crack up
[phrasal verb] informal 1 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
▪ When we saw the picture, we both cracked up. ▪ That joke really cracks me up. [=I think that joke is very funny] 2 : to become mentally ill : to lose control of your thoughts and emotions so that you cannot continue to live in a normal way
▪ The stress was getting worse, and she felt herself cracking up. [=going crazy] 3 crack up or crack up (something) also crack (something) up US, informal : to damage (a vehicle) by crashing
▪ I cracked up [=crashed] on a curve in the road. ▪ I cracked up [=crashed] the car. — see also crack-up 4 ◊Something that is what/all/everything (etc.) it's cracked up to be is as good as people say it is.
▪ Is the movie really all it's cracked up to be? = Is it really as good as it's cracked up to be? This phrase is usually used in negative statements. ▪ The new restaurant is not all it's cracked up to be. When we went, the service was awful and our food was cold.
▪ When we saw the picture, we both cracked up. ▪ That joke really cracks me up. [=I think that joke is very funny]
▪ The stress was getting worse, and she felt herself cracking up. [=going crazy]
▪ I cracked up [=crashed] on a curve in the road. ▪ I cracked up [=crashed] the car. — see also crack-up
▪ Is the movie really all it's cracked up to be? = Is it really as good as it's cracked up to be? This phrase is usually used in negative statements. ▪ The new restaurant is not all it's cracked up to be. When we went, the service was awful and our food was cold.
crack wise
US, informal : to say something that is funny and smart : to make a wisecrack
▪ She's always cracking wise.
▪ She's always cracking wise.
get cracking
informal : to start doing something
▪ You ought to get cracking [=get going; get moving] on that assignment. [=you should start working on that assignment right away]
▪ You ought to get cracking [=get going; get moving] on that assignment. [=you should start working on that assignment right away]
