Pronunciation: (thôt'lis), [key]
1. lacking in consideration for others; inconsiderate; tactless: a thoughtless remark.
2. characterized by or showing lack of thought: a shallow, thoughtless book.
3. not thinking enough; careless or heedless: thoughtless of his health.
4. devoid of or lacking capacity for thought.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.