gab vs mentum

gab

noun
  • The mouth or gob. 

  • Idle chatter. 

  • One of the open-forked ends of rods controlling reversing in early steam engines. 

verb
  • To talk or chatter a lot, usually on trivial subjects. 

mentum

noun
  • The chin. 

  • The central part of the labium in insects. 

  • A chin-like projection below the mouth of certain mollusks. 

  • A projection in front of the flower in some orchids. 

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