fingernail vs grappler

fingernail

noun
  • The hard, flat translucent covering near the tip of a human finger, useful for scratching and fine manipulation. 

grappler

noun
  • One who grapples. 

  • A wrestler; one who fights by wrestling. 

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