quop vs thud

quop

verb

  • To throb or beat. 

thud

verb

  • To make the sound of a dull impact. 

noun

  • The sound of a dull impact. 

  • A slower, dull impact with a wide surface area. 

  • A hard, dull impact. 

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