crack up

verb

1. (intr) to break into pieces

2. informal,  (intr) to undergo a physical or mental breakdown

3. informal,  (tr) to present or report, esp in glowing terms

   it's not all it's cracked up to be

4. informal,  to laugh or cause to laugh uproariously or uncontrollably

noun

1. informal,  a physical or mental breakdown

Idioms and Phrases

Suffer an emotional breakdown, become insane, as in He might crack up under the strain . This usage alludes to the result of cracking one's skull; from the early 1600s to crack alone was used in this way. [ Slang ; early 1900s]

Damage or wreck a vehicle or vessel. For example, I'm always afraid that I'll crack up the car .

Experience a crash, as in We cracked up on the freeway in the middle of the ice storm .

Also, crack someone up . Burst or cause to burst out laughing, as in The audience cracked up , or That joke really cracked me up . [ Slang ; c. 1940] Also see break up , def. 6. All of these expressions derive from crack in the sense of “break into pieces” or “collapse,” a usage dating from the late 1600s. Also see cracked up .

Example Sentences

A sprinkle of heavenly magic, and Arj can be taught a valuable lesson—by trading places with Jeff and finding out that wealth isn’t all it’s cracked up to be.

Read more on The Wall Street Journal

“And she looks at it and starts cracking up. And she’s like, ‘See, she’s the problem.’

Read more on Los Angeles Times

When he saw the result in the mirror, he cracked up: “Oh my God, I’m Geppetto. I look just like the Disney version.”

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"I just cracked up laughing of course, because that's what any woman would want to hear, but it's our life, so it's pretty wonderful. He was a man of his word."

Read more on BBC

Best joke of the sketch: the hosts cracking up with laughter at the thought of paying back student loans.

Read more on Los Angeles Times

Related Words

• freak out 
• go crazy www.thesaurus.com