A person who damages another's reputation or honor; one who besmirches.
From besmirch plus the agent noun suffix -er. Creates a noun naming the person who performs the action of besmirching.
Most agent nouns formed with -er are no longer productive in modern English—we don't coin 'begrudgers' or 'befuddle-ers,' yet 'besmircher' survives because besmirch itself survived. It shows how specialized moral language keeps archaic forms alive.
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