The Collaborative International Dictionary of English v.0.48:
Foolhardiness \Fool"har`di*ness\, n. Courage without sense or judgment; foolish rashness; recklessness. --Dryden. [1913 Webster]WordNet (r) 3.0 (2006):
foolhardiness n 1: the trait of giving little thought to danger [syn: recklessness, foolhardiness, rashness]