king hit vs king-hit

king hit

noun
  • A blow intended to incapacitate in one hit, often delivered without warning. 

verb
  • To attack a victim and knock them unconscious with a single punch. 

king-hit

noun
  • A powerful punch; a knockout blow. 

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