Reckless

reckless (rk'ls) adj. Heedless or careless. Headstrong; rash. Indifferent to or disregardful of consequences: a reckless driver.

[Middle English reckeles, from Old English receleas.]
reck'lessly adv.
reck'lessness n.

SYNONYMS reckless, rash, precipitate, foolhardy, temerarious. These adjectives mean given to or marked by unthinking boldness. Reckless suggests wild carelessness and disregard for consequences: conceiving measures to protect the fur-bearing animals from reckless slaughter
(Getrude Atherton). Rash implies haste, impetuousness, and insufficient consideration: Take calculated risks. That is quite different from being rash (George S. Patton). Precipitate connotes headlong haste without due deliberation: destroyed in a precipitate burning of his papers a few days before his death (James Boswell). Foolhardy implies injudicious or imprudent boldness: a foolhardy attempt to wrest the gun from the mugger. Temerarious suggests reckless presumption: this temerarious foeman who dared intervene between himself [the elephant] and his intended victim (Edgar Rice Burroughs).