/ Dictionary / Index T thoughtless: Meaning and Definition of Find definitions for: thought•less Pronunciation: (thôt'lis), [key] — adj. lacking in consideration for others; inconsiderate; tactless: a thoughtless remark. characterized by or showing lack of thought: a shallow, thoughtless book. not thinking enough; careless or heedless: thoughtless of his health. devoid of or lacking capacity for thought. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: thoughtless (Thesaurus) thoughtful thought-out Related Content Daily Word Quiz: opulent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language