monstrous vs plug-ugly

monstrous

adj
  • Hideous or frightful. 

  • Enormously large. 

  • Of, or relating to a mythical monster; full of monsters. 

  • Freakish or grotesque. 

plug-ugly

adj
  • Very ugly. 

noun
  • An ugly person. 

  • A member of an American nativist street gang that operated in the west side of Baltimore, Maryland, from 1854 to 1865. 

How often have the words monstrous and plug-ugly occurred in a corpus of books? (source: Google Ngram Viewer )