im·pet·u·ous 
(
ĭm-p
ĕch
-
əs)
adj.1. Acting or done quickly with little or inadequate thought.
2. Having or marked by violent force: impetuous, heaving waves.
[Middle English, violent, from Old French impetueux, from Late Latin impetuōsus, from Latin impetus, impetus; see IMPETUS.]
im·petu·ous·ly adv.
im·petu·ous·ness n.