Definition of defies:
(v) :
(transitive) To refuse to obey.
(v) :
(transitive) To challenge (someone) or brave (a hazard or opposition).
(v) :
To not conform to or follow a pattern, set of rules or expectations.
(n) :
(obsolete) A challenge.
(v) :
(transitive, obsolete) To renounce or dissolve all bonds of affiance, faith, or obligation with; to reject, refuse, or renounce.