expression, godan verb (-ru)
besmirch; sully; disgrace
Idiomatic expression meaning to bring shame or dishonor upon someone, often by damaging their reputation. Frequently used in the pattern 顔に泥を塗る (to bring disgrace to someone's face/honor).
See also: 顔に泥を塗る
彼の不正が会社の顔に泥を塗った。
His misconduct brought disgrace upon the company.
そんなことをしたら、家族の顔に泥を塗ることになる。
If you do that, you'll bring shame on your family.