transitive verb

Damage the reputation of (someone or something) in the opinion of others.

he had besmirched the good name of his family

sully,tarnish,blacken,drag through the mire,drag through the mud,stain,taint,smear,befoul,soil,contaminate,pollute,disgrace,dishonour,bring discredit to,stigmatize,injure,damage,debase,spoil,ruin