knock for a loop vs whop

knock for a loop

verb
  • To astonish; to stagger or overwhelm; to confuse or disorient. 

whop

verb
  • To throw or move (something) quickly, usually with an impact. 

  • To administer corporal punishment 

noun
  • A blow or strike. 

How often have the words knock for a loop and whop occurred in a corpus of books? (source: Google Ngram Viewer )