besmirch

verb

1. (literary, transitive)To make dirty.
2. (transitive)To tarnish something, especially someone's reputation.

   “The newspaper was on a campaign to besmirch the actor.”

   “Our gayness and our gilt are all besmirch'd With rainy marching in the painful field”

   “"It may be," he replied, "because I will not encounter the dishonor that besmirches the husband of a faithless woman.[…]"”

   “Sir Guy might still have slain him without besmirching his knightly honor”