1. Taking insufficient care; negligent: a careless housekeeper; careless proofreading.
2. Marked by or resulting from lack of forethought or thoroughness: a careless mistake.
3. Showing a lack of consideration: a careless remark.
4. Unconcerned or indifferent; heedless: careless of the consequences.
5. Unstudied or effortless: danced with careless grace.
6. Exhibiting a disposition that is free from cares; cheerful: a careless grin; a careless wave of the hand.
Synonyms: careless, heedless, thoughtless, inadvertent
These adjectives apply to people who perform actions marked by insufficient care or attention or to the actions themselves. Careless often implies negligence or casual indifference: "It is natural for careless writers to run into faults they never think of" (George Berkeley).
Heedless can suggest willful or reckless disregard: "She ... watched the top of the hill for someone drunk or heedless coming over it in part of her lane" (Andre Dubus).
Thoughtless applies to actions taken without due consideration; it frequently implies lack of concern for others: "a thoughtless remark about the war that will worry an already worried child" (Kristin Henderson).
Inadvertent implies unintentional lack of care or attention: "For the deterrence theorists, the greatest worry was inadvertent war, a cataclysm that might follow from misperception" (Eliot A. Cohen).
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.