Serious quarrel

WordNet Word definitions in WordNet
n. a serious quarrel (especially one that ends a friendship)

Wiktionary Word definitions in Wiktionary
n. An angry argument.

Longman Dictionary of Contemporary English Word definitions in Longman Dictionary of Contemporary English
noun EXAMPLES FROM OTHER ENTRIES ▪ After the bust-up , I didn't see Rick for several weeks. ▪ Christie was involved in an angry bust-up with reporters and photographers outside the courtroom. ▪ She and her boyfriend had a big bust-up over who was supposed ...

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
bust-up \bust-up\ n. a serious quarrel (especially one that ends a friendship). With some antick bustoes in the niches. --Ashmole.