Taking insufficient care; negligent: a careless housekeeper; careless proofreading.
Marked by or resulting from lack of forethought or thoroughness: a careless mistake.
Showing a lack of consideration: a careless remark.
Unconcerned or indifferent; heedless: careless of the consequences.
Unstudied or effortless: danced with careless grace.
Exhibiting a disposition that is free from cares; cheerful: a careless grin; a careless wave of the hand.
derivatives
caréless·ly
adverb
caréless·ness
noun
synonyms:
careless, heedless, thoughtless, inadvertent These adjectives apply to what is marked by insufficient care or attention. Careless often implies negligence: “It is natural for careless writers to run into faults they never think of” (George Berkeley) Heedless often suggests recklessness: “We have always known that heedless self-interest was bad morals; we know now that it is bad economics” (Franklin D. Roosevelt) Thoughtless applies to actions taken without due consideration: “But thoughtless follies laid him low / And stain'd his name” (Robert Burns) Inadvertent implies unintentional lack of care: With an inadvertent gesture, she swept the vase off the table.
The American Heritage® Dictionary of the English Language, Fourth Edition