- not stopping to think; heedless
- showing lack of thought, attention, or consideration
- lacking the ability to think; nonrational
- Not taking due thought; thoughtless or heedless: proceeded, unthinking, into the trap.
- Exhibiting a lack of thought: unthinking bravado.
- Incapable of the power of thought.
(comparative more unthinking, superlative most unthinking)
- Present participle of unthink.