[adjective] 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) Synonyms:hotheaded, impulsive, madcap, tearaway, brainish
[adjective] marked by violent force; "impetuous heaving waves"
