Impetuous
WordNet
adjective
(1) Characterized by undue haste and lack of thought or deliberation
"A hotheaded decision"
"Liable to such impulsive acts as hugging strangers"
"An impetuous display of spending and gambling"
"Madcap escapades"; (`brainish' is archaic)
(2) Marked by violent force
"Impetuous heaving waves"