befilth vs befoul

befilth

verb
  • To cover with filth; make filthy; begrime. 

befoul

verb
  • To make foul; to soil; to contaminate, pollute. 

  • To entangle or run against so as to impede motion. 

  • To defecate on, to soil with excrement. 

  • To stain or mar (for example with infamy or disgrace). 

How often have the words befilth and befoul occurred in a corpus of books? (source: Google Ngram Viewer )