- not stopping to think; careless
- not given thought; ill-considered; rash
- not considerate of others; inconsiderate
- Rare stupid; senseless
- Marked by or showing lack of due forethought or care; careless: a thoughtless mistake; a thoughtless bumbler. See Synonyms at careless.
- Inconsiderate of the feelings of others: a thoughtless remark.
- Lacking thought: staring blankly in a thoughtless daze.
(comparative more thoughtless, superlative most thoughtless)
thought +"Ž -less