Similar word to unthinking:

blundering, brutish, feckless, foolish, heedless, impulsive, inadvertent, inconsiderate, indelicate, insensitive, instinctive, mechanical, napping, negligent, oblivious, outrageous, rash, rude, selfish, senseless, tactless, thoughtless, uncaring, unconscious, undiplomatic, unheeding, unintended, unmeant, unmindful, unpremeditated, unreasoning, untactful, unwise, vacant, witless