If you besmirch someone or their reputation, you say that they are a bad person or that they have done something wrong, usually when this is not true. He has accused local people of trying to besmirch his reputation. = sully. besmirch sb's honour/reputation to spoil the good opinion that people have of someone (smirch (15-20 centuries), perhaps from esmorcher )
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"