thoughtless
Concise Oxford English Dictionary © 2008 Oxford University Press:
thoughtless/ˈθɔːtləs/
▶adjective
- 1 not showing consideration for other people.
- 2 without consideration of the consequences.
– derivatives
thoughtlessly adverb,
thoughtlessness noun.
thoughtlessly adverb,
thoughtlessness noun.
'thoughtless' also found in these Oxford entries:

