blemish, mar, defect - a mark or flaw that spoils the appearance of something (especially on a person's body); "a facial blemish"

blotch, splodge, splotch - an irregularly shaped spot

fingermark, fingerprint - a smudge made by a (dirty) finger

inkblot - a blot made with ink

error, mistake, fault - a wrong action attributable to bad judgment or ignorance or inattention; "he made a bad mistake"; "she was quick to point out my errors"; "I could understand his English in spite of his grammatical faults"

smear - stain by smearing or daubing with a dirty substance

accuse, charge - blame for, make a claim of wrongdoing or misbehavior against; "he charged me director with indifference"

assassinate - destroy or damage seriously, as of someone's reputation; "He assassinated his enemy's character"

libel - print slanderous statements against; "The newspaper was accused of libeling him"

badmouth, drag through the mud, malign, traduce - speak unfavorably about; "She badmouthes her husband everywhere"