1. Characterized by sudden and forceful energy or emotion; impulsive and passionate.
2. Having or marked by violent force: impetuous, heaving waves.
[Middle English, violent, from Old French impetueux, from Late Latin impetusus, from Latin impetus, impetus; see impetus.]
Synonyms: impetuous, heedless, hasty, headlong, precipitate, sudden These adjectives describe abruptness or lack of deliberation. Impetuous suggests forceful impulsiveness or impatience: [a race driver who was] flamboyant, impetuous, disdainful of death (Jim Murray). Heedless implies carelessness or lack of responsibility or proper regard for consequences: Hobbling down stairs with heedless haste, I set my foot full in a pail of water (Richard Steele). Hasty and headlong both stress hurried, often reckless action: Hasty marriage seldom proveth well (Shakespeare). In his headlong flight down the circular staircase, ... [he] had pitched forward violently, struck his head against the door to the east veranda, and probably broken his neck (Mary Roberts Rinehart). Precipitate suggests impulsiveness and lack of due reflection: a precipitate decision. Sudden applies to what becomes apparent abruptly or unexpectedly: is given to sudden paroxysms of anger.
impetuous /mptus/ adj. done quickly often without thinking, (syn.) impulsive: She made an impetuous decision in marrying so young.-adv.impetuously.