1 defy somebody/something to refuse to obey or show respect for somebody in authority, a law, a rule, etcI wouldn't have dared to defy my teachers.Hundreds of people today defied the ban on political gatherings.2 defy belief, explanation, description, etc. to be impossible or almost impossible to believe, explain, describe, etca political move that defies explanationThe beauty of the scene defies description.3 defy something to successfully resist something to a very unusual degreeThe baby boy defied all the odds and survived (= stayed alive when it seemed certain that he would die).
dɪˈfaɪ ; dɪˈfaɪdefies, defying, defied, defied
I defy you/anyone to do something
used to say that somebody should try to do something, as a way of emphasizing that you think it is impossible to do itI defy anyone not to cry at the end of the film.I defy you to leave without buying something.