To renounce; reject; decline; repudiate; cast off.
To revolt at; reject from dislike; disapprove.
To challenge to contest or trial with hands; dare to generally meet in fight.
To challenge to an action or process of any sort; dare to accomplish some thing (usually with an implication of belief that it cannot be done, or that action will fail of the purpose).
To dare; brave; manifest a contempt of or indifference to (resistance, assault, or hostile power); set at naught; resist effectively: as, to defy the arguments of an opponent; to defy the power of a magistrate.