flatten out vs thump

flatten out

verb
  • To win a fight, usually by punching someone until they are knocked over 

  • To make flat (something rough, folded or bumpy). 

  • To become more even. 

thump

verb
  • To hit (someone or something) as if to make a thump. 

  • To throb with a muffled rhythmic sound. 

  • To cause to make a thumping sound. 

  • To thud or pound. 

noun
  • A blow that produces a muffled sound. 

  • The sound of such a blow; a thud. 

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