Answer: besmirch

AnswerCrossword Clue
BESMIRCHSully
BESMIRCHSully.
BESMIRCHTarnish
BESMIRCHBring dishonor upon
besmirchMake (something) dirty or discolored
besmirchto sully (to soil (to make dirty (soiled)))
besmirchDamage the reputation of (someone or something) in the opinion of others