The word defiantly, that is, an action taken under bold, audacious, or daring conditions, could be easily associated with a challenge since this implies an event or a circumstance that is difficult to overcome, achieve, or accomplish. In a sentence, then, one could say: he defiantly faced the upcoming challenge.
Defiantly. Profusely is big, perfunctory is lazily doing something, petulantly is to do something with a bad temper, and defiantly is doing something even though you don't want to
