- lacking in consideration for others; inconsiderate; tactless: a thoughtless remark.
- characterized by or showing lack of thought: a shallow, thoughtless book.
- not thinking enough; careless or heedless: thoughtless of his health.
- devoid of or lacking capacity for thought.
- inconsideratea thoughtless remark
- having or showing lack of thoughta thoughtless essay
- unable to think; not having the power of thought
adj.“inconsiderate,” 1794, from thought + -less. Related: Thoughtlessly; thoughtlessness.