filthen

Verb

filthen (third-person singular simple present filthens, present participle filthening, simple past and past participle filthened)

1. (nonstandard, rare, transitive) To cover with filth; besmut; besmirch; make filthy.
   • Rock oil was considered, then, a local nuisance, a malodorous black gunk that floated like a rumor down the creek, filthening whatever it touched: a farmer's overalls, a cow's hide, a child's shoes.2016, Jennifer Haigh, Heat and Light