by itsjade January 22, 2009

Bursting into a prolonged fit of intense, uncontrollable laughter. Instigating this sort of reaction in someone is called "Cracking that person up."
by lollylollylollyPOP!!! July 24, 2009

by Diego September 04, 2003

laughing mad hard. Almost to the point of crying. Laughing you split ends off. more than giggleing or laughing
Guy 1: hey, whats wrong wiff aly?
Guy 2: Oh we where talking about how disgusting Michelle's nose is and then she started cracking up
Guy 2: Oh we where talking about how disgusting Michelle's nose is and then she started cracking up
by Petrusha July 01, 2008

by Ark T May 27, 2010

by milkNcereal2319 June 27, 2005

To burst into loud, hysterical or aggressive verbal abuse. Used primarily in Ireland and the UK. Similar with the American "freak the fuck out," however only used in negative situations.
"Yer wan at the pub cracked up at me when I asked how much she charged for an hour."
"Don't you dare crack up at me! I'm not the one sleepin' with my sister!"
"Don't you dare crack up at me! I'm not the one sleepin' with my sister!"
by Lolitaslut May 06, 2009
