compliment vs rap over the knuckles

compliment

noun
  • An expression of praise, congratulation, or respect. 

  • Complimentary language; courtesy, flattery. 

verb
  • To pay a compliment (to someone); to express a favourable opinion (of someone). 

rap over the knuckles

How often have the words compliment and rap over the knuckles occurred in a corpus of books? (source: Google Ngram Viewer )