praise vs slag off

praise

noun
  • Commendation; favourable representation in words. 

  • Worship. 

verb
  • To give praise to; to commend, glorify, or worship. 

slag off

verb
  • To purify by melting and removing slag. 

  • To talk insultingly to or about someone or something; usually one who is not present. 

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