Answer: besmirches

AnswerCrossword Clue
BESMIRCHESAmong trees, some loveless stranger gets dirty (10)
besmirchesMake (something) dirty or discolored
besmirchesBESMIRCH, to sully (to soil (to make dirty (soiled)))
besmirchesDamage the reputation of (someone or something) in the opinion of others