Source : Webster's Revised Unabridged Dictionary (1913)

Defiant \De*fi"ant\, a. [Cf. F. d['e]fiant, p. pr. of d['e]fier.
   See {Defy}.]
   Full of defiance; bold; insolent; as, a defiant spirit or
   act.

         In attitude stern and defiant.           --Longfellow.
   -- {De*fi"ant*ly}, adv. -- {De*fi"ant*ness}, n.

Source : WordNet®

defiant
     adj : boldly resisting authority or an opposing force; "brought up
           to be aggressive and defiant"; "a defiant attitude"
           [syn: {noncompliant}] [ant: {compliant}]