somersault vs waver

somersault

verb
  • To perform a somersault. 

noun
  • Starting on one's feet, an instance of rotating one's body 360 degree while airborne or on the ground, with one's feet passing over one's head. 

waver

verb
  • To sway back and forth; to totter or reel. 

  • To fluctuate or vary, as commodity prices or a poorly sustained musical pitch. 

  • To shake or tremble, as the hands or voice. 

  • To falter; become unsteady; begin to fail or give way. 

  • To be indecisive between choices; to feel or show doubt or indecision; to vacillate. 

  • To flicker, glimmer, quiver, as a weak light. 

noun
  • Someone who specializes in waving (hair treatment). 

  • Someone who waves, enjoys waving, etc. 

  • An act of wavering, vacillating, etc. 

  • A tool that accomplishes hair waving. 

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