curveball vs twirl

curveball

verb
  • To throw a curveball. 

noun
  • A forespin pitch thrown by rotating the index and middle fingers down and resulting in motion down "curve" 

  • An unexpected turn of events initiated by an opponent or chance; an exception or outlier. 

twirl

verb
  • To pitch. 

  • To twist round. 

  • To rotate rapidly. 

  • To perform a twirl. 

noun
  • A little twist of some substance; a swirl. 

  • A movement where a person spins round elegantly; a pirouette. 

  • Any rotating movement; a spin. 

  • A prison guard. 

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