Unthinking
Pronunciation : Un*think"ing
Part of Speech : a.
Definition : 1. Not thinking; not heedful; thoughtless; inconsiderate; as, unthinking youth.
2. Not indicating thought or reflection; thoughtless. With earnest eyes, and round unthinking face, He first the snuffbox opened, then the case. Pope. -- Un*think"ing*ly, adv. -- Un*think"ing*ness, n.
Source : Webster's Unabridged Dictionary, 1913