grot vs gruel

grot

noun
  • Any unpleasant substance or material. 

  • A miserable person. 

  • A grotto. 

gruel

noun
  • something that lacks substance 

  • A thin, watery porridge, formerly eaten primarily by the poor and the ill. 

  • punishment 

  • semen 

verb
  • ejaculate 

  • To exhaust, use up, disable 

  • to punish 

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