Synonyms: break down, snap, lose it
Definition: lose control of one's emotions
Usage: When she heard that she had not passed the exam, she lost it completely; When her baby died, she snapped
Similar words: act, behave, do
Definition: behave in a certain manner; show a certain behavior; conduct or comport oneself
Usage: You should act like an adult; Don't behave like a fool; What makes her do this way?; The dog acts ferocious, but he is really afraid of people