From Longman Dictionary of Contemporary Englishgo off on somebody phrasal verb American English informal1 to criticize or speak to someone in a very angry way2 go off on one British English informal to suddenly start speaking and behaving in a very angry way When I told him I wouldn’t be back till midnight, he went off on one. → go→ See Verb table
Examples from the Corpus
go off on • So one day when my grandfather came in and began insulting my grandmother, my father went off on him. 