Definition of bust up:
(v) :
(US, informal, transitive) To physically damage or ruin; to be ruined; to go bankrupt; to end (something).
(v) :
(US, informal, intransitive) To break up (end a relationship).
(v) :
(slang) To express sudden and intense emotions; to burst into loud laughter.
(v) :
(slang, Australia) To spend money wildly, especially on alcoholic drinks.
(v) :
(slang, African-American Vernacular) To shoot (someone).