thoughtless
adjective uk/ˈθɔːt.ləs/ us/ˈθɑːt.ləs/
C2 欠考虑的;不为他人着想的;粗心的
not considering how your actions or words may upset someone
It was thoughtless not to call and say you'd be late. 要迟到都不打个电话，你太欠考虑了。
She's not intentionally unkind - she's just a little thoughtless sometimes. 她不是故意不友好——她只是有时有点粗心。