adverb
1. in a thoughtless manner
-
he stared thoughtlessly at the picture
• Syn: ↑unthinkingly, ↑unthinking
• Ant: ↑thoughtfully
• Derived from adjective: ↑unthinking (for: ↑unthinkingly), ↑thoughtless
2. showing thoughtlessness
-
he treated his parents thoughtlessly
• Ant: ↑thoughtfully
• Derived from adjective: ↑thoughtless
Useful english dictionary. 2012.