Phrasal Verb: Crack up

Meaning: Have a nervous breakdown

Example: He CRACKED UP after his son died and had to take a couple of months off work.

Meaning: Have bad reception on a mobile phone

Example: You'll have to talk louder- you're CRACKING UP.

Meaning: Burst out laughing

Example: Everybody CRACKED UP when he told the joke.

Meaning: Damage a car badly

Example: He CRACKED his car UP last night when he came off the road.