Synonyms for Unthinking:

adj.

blind (adjective)
reckless.
careless (adjective)
inconsiderate, unheeding, foolish, impulsive, vacant, rash, rude, heedless, uncaring, thoughtless, unmindful, feckless, unwise.
foolish (adjective)
rash, impulsive, unwise.
inattentive (adjective)
careless.
shallow (adjective)
shallow.
thoughtless (adjective)
inane, empty-headed, fatuous, vacant, heedless, unreasonable, brainless, thoughtless, unoccupied, unthoughtful, rude, vacuous, mindless, blank, illogical, careless.
uncritical (adjective)
undiscriminating.

n.

ill-considered, foolish, hasty, impetuous, undiscriminating, shallow. heedless, irresponsible, careless, reckless, unmindful, careful, feckless, unconcerned, inattentive. unheeding, forgetful, unobservant. courtesy, Disregardful. unthinking (noun)
thoughtless, uncaring, lumpen, unreflective, unthoughtful, inconsiderate, lumpish, unthinkingly, thoughtlessly.

Other synonyms:

Disregardful, undiscriminating, unobservant, feckless, ill-considered, shallow, unheeding. unmindful, impulsive, reckless, foolish, heedless, impetuous, irresponsible. inattentive. forgetful, unconcerned. precipitate
rash.
Other relevant words:
hasty, rude, thoughtlessly, ill-considered, rash, undiscriminating, unwise, unconcerned, lumpen, heedless, feckless, shallow, uncaring, reckless, unobservant, irresponsible, unthinkingly, unmindful, impulsive, unheeding, forgetful, inconsiderate, unreflective, inattentive, careless, foolish, impetuous, Disregardful, lumpish.

Usage examples for unthinking

  1. There are no classes such as you have in mind in the Church, even though a few unthinking members seem to imply it by their actions; but there is no real class distinction in the Church of Jesus Christ of Latter- day Saints, only such that are based on the doing of the right and the wrong. – Dorian by Nephi Anderson
  2. But still, there's a gulf between extreme probability and absolute certainty that's a bit wider than the unthinking reckon for. – Ravensdene Court by J. S. (Joseph Smith) Fletcher
  3. Nominally, that is to say in the eyes of unthinking men, the North will conquer the South; but your existing armies will not do it. – Who Goes There? by Blackwood Ketcham Benson