Meaning of Idiom ‘Crack Up’
1. To go insane or have an emotional or mental breakdown.
Compare Come Apart at the Seams.
2. Cause damage to or wreck a vehicle; to be in a vehicular crash.
3. To laugh heartily or cause someone to laugh.
Compare Not All It’s Cracked Up To Be.
Sentence Examples
“Ramos completely cracked up after he was caught embezzling.”
“There was a crack up on the interstate today. I was stuck in traffic for hours.”
“Mitchell is hysterical. He cracks me up every time I see him.”
Origin
To crack up originally meant to toast or praise. The present idiom seems unrelated. Here, the word crack has the sense of “breaking into pieces.”
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