Pronunciation: (un-thing'king), [key]
1. thoughtless; heedless; inconsiderate: an unthinking, tactless person.
2. indicating lack of thought or reflection: a dull, unthinking expression on his face.
3. not endowed with the faculty of thought: unthinking matter.
4. not exercising thought; not given to reflection: This book will not profit an unthinking person.
5. not thinking; unmindful: chores done in an unthinking manner.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.