to shout angrily and wildly about someone or something. Barbara rants and raves when her children don't obey her.Bob rants and raves about anything that displeases him.
Talk loudly and vehemently, especially in anger, as in There you go again, ranting and raving about the neighbor's car in your driveway. This idiom is a redundancy, since rant and rave mean just about the same thing, but probably survives on account of its alliterative appeal.