Un‐think″ing, a. 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.