scum vs vermin

scum

noun
  • A reprehensible person or persons. 

  • Semen. 

  • A layer of impurities that accumulates at the surface of a liquid (especially molten metal or water). 

  • A greenish water vegetation (such as algae), usually found floating on the surface of ponds 

  • The topmost liquid layer of a cesspool or septic tank. 

verb
  • To remove (something) as scum. 

  • To startscum or savescum. 

  • To remove the layer of scum from (a liquid etc.). 

  • To become covered with scum. 

vermin

noun
  • Obnoxious, or mean and offensive person or people. 

  • Any one of various common types of small insects or animals which cause harm and annoyance. 

  • Animals that prey on game, such as foxes or weasels. 

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