See impetuous in American Heritage Dictionary 4 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.
See impetuous in Webster's New World Roget's A-Z Thesaurus II
adjective
Characterized by unthinking boldness and haste:
brash, foolhardy, harum-scarum, hasty, headlong, hotheaded, ill-considered, improvident, impulsive, incautious, madcap, precipitant, precipitate, rash1, reckless, slapdash, temerarious, unconsidered. See careful
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