Merriam-Webster Online Dictionary
careless (adjective)1.
a) free from care - untroubled careless days
b) - indifferent unconcerned careless of the consequences
2.
not taking care
3.
not showing or receiving care
a) - negligent slovenly careless writing
b) - unstudied spontaneous a careless grace
c) obsolete - unvalued disregarded
Merriam-Webster Online Thesaurus
careless (adjective)1.
not paying or showing close attention especially for the purpose of avoiding trouble
SYNONIMS:
heedless, incautious, mindless, unguarded, unsafe, unwaryRELATED WORDS:
bold, impetuous, rash, reckless; inattentive, regardless; blithe, inconsiderate, thoughtless; absentminded, forgetful, unmindful; lax, neglectful, negligent, remiss, slipshod; imprudent, indiscreet, injudicious; inadvertent, unintentional, unplannedNEAR ANTONYMS:
attentive, chary, observant, vigilant, watchful; foresighted, forethoughtful, provident; calculating, scheming, shrewd; considerate, thoughtful; ultracareful, ultracautious2.
failing to give proper care and attention
SYNONIMS:
careless, derelict, disregardful, lax, lazy, neglectful, neglecting, remiss, slackRELATED WORDS:
heedless, incautious, irresponsible, reckless, wild; unguarded, unwary; forgetful; disregardful, disregarding, inattentive, oblivious, thoughtless, unheeding, unmindful, unthinking; apathetic, disinterested, indifferent, unconcerned, uninterested; delinquent; looseNEAR ANTONYMS:
meticulous, painstaking, punctilious; cautious, chary, circumspect, gingerly, guarded; alert, heedful, heeding, mindful, observant, regardful, regarding, vigilant, wary, watchful; foresighted, forethoughtful, provident, responsible; thinking, thoughtful; concerned, interested