crack someone up

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crack up

1. verb To laugh very hard. We all cracked up at Josh's joke.
2. verb To cause someone to laugh very hard. In this usage, a noun or pronoun can be used between "crack" and "up." Josh's joke cracked us all up. That comedian just cracks me up.
3. verb To experience a mental or emotional breakdown. All those days of sleep deprivation finally caused me to crack up. She's terrified to leave the house all of a sudden—I think she's cracking up.
4. verb To destroy something. He drove into a tree and cracked up his car.
5. verb To be in an accident. I cracked up after losing control of my car.
6. noun An accident. When used as a noun, the phrase is typically hyphenated. I was in a crack-up when I lost control of my car and hydroplaned.
See also: crack, up

crack someone up

tv. to make someone laugh. The lecturer would talk along sort of boring like, and then all of a sudden he would crack up everybody with a joke.
See also: crack, someone, up