smirch

(noun) a blemish made by dirt. Synonyms: smudge, spot, blot, daub, smear, slur. Example: "He had a smudge on his cheek."

(noun) an act that brings discredit to the person who does it. Synonyms: blot, smear, spot, stain. Example: "He made a huge blot on his copybook."

(verb) smear so as to make dirty or stained. Synonyms: besmirch.

(verb) charge falsely or with malicious intent; attack the good name and reputation of someone. Synonyms: defame, slander, asperse, denigrate, calumniate, smear, sully, besmirch. Example: "The journalists have defamed me!" "the article in the paper sullied my reputation."