incurvate vs twirl

incurvate

verb
  • To bend (especially inwards); to give a curved shape to. 

  • to have a curved or bent shape; to bend or curve inwards. 

adj
  • bending inwards. 

  • Curved; bent; crooked. 

twirl

verb
  • To twist round. 

  • To pitch. 

  • 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 incurvate and twirl occurred in a corpus of books? (source: Google Ngram Viewer )