Synonyms for thoughtless

modified

1. Destitute of thought

   irrational, unreasoning, unreasonable, vacuous, inane, incomprehensible, witless, undiscerning, bovine, foolish, doltish, babbling, bewildered, confused, puerile, senseless, driveling, inept, dull, heavy, obtuse, feeble-minded, flighty, empty-headed*, lame-brained*, barmy*, nutty*, loony*, rattled*, sappy*, dizzy*; see also stupid 1.

   Antonyms rational*, reasoning, shrewd.

2. Inconsiderate

   heedless, negligent, inattentive, careless, indiscreet, neglectful, self-centered, egocentric, selfish, asocial, antisocial, unmindful, unheeding, reckless, deaf, blind, indifferent, unconcerned, listless, apathetic, boorish, discourteous, rude, primitive, unrefined; see also rude 2.

   Antonyms careful*, thoughtful, unselfish.