From Longman Dictionary of Contemporary Englishbust up phrasal verb informal1RELATIONSHIP British English if people bust up, they end their relationship or friendship syn break upThey bust up after six years of marriage. →bust-up(1)2bust something ↔ upPREVENT to prevent an illegalactivity or bad situation from continuing syn break upA couple of teachers stepped in to bust up the fight.3bust something ↔ up American EnglishDAMAGE to damage or break somethingA bunch of bikers busted up the bar.4American English to start laughing a lot syn crack upElaine busted up laughing at the sight of him. →bust→ See Verb table
Examples from the Corpus
bust up• She said Gloria was always trying to bust up their conversations.bust-upˈbust-up noun [countable] informal1RELATIONSHIPthe end of a relationshipbust-up ofthe bust-up of their marriage → bust upat bust12ARGUE British English a very bad quarrel or fightCathy and I had a real bust-up yesterday.