grot vs venin

grot

noun
  • Any unpleasant substance or material. 

  • A miserable person. 

  • A grotto. 

venin

noun
  • A supposedly identical toxic substance obtained by cleavage of an albumose. 

  • A toxic substance found in the venom of poisonous snakes. 

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