nub vs sweet spot

nub

noun
  • The clitoris. 

  • a pointing stick 

  • A small lump or knob. 

  • The essence or core of an issue, argument etc. 

verb
  • To push; to nudge. 

  • To beckon. 

  • To hit the ball weakly. 

sweet spot

noun
  • The clitoris, prostate gland, or other center of sexual pleasure. 

  • Any place that is optimal for obtaining a certain desirable effect or result. 

  • Any of several places on a bat, racquet, etc., with which to hit a ball, resulting in the latter rebounding with some optimal desirable effect, such as minimum vibration or maximum velocity. 

  • Any set of conditions that is optimal for obtaining a certain desirable effect or result. 

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