S: (n) blot, smear, smirch, spot, stain (an act that brings discredit to the person who does it) "he made a huge blot on his copybook"
Verb
S: (v) smirch, besmirch (smear so as to make dirty or stained)
S: (v) defame, slander, smirch, asperse, denigrate, calumniate, smear, sully, besmirch (charge falsely or with malicious intent; attack the good name and reputation of someone) "The journalists have defamed me!"; "The article in the paper sullied my reputation"