discretion vs slip of the tongue

discretion

noun
  • The quality of being discreet. 

  • The freedom to make one's own judgements. 

  • Individual justice from experience in quality of perception: discrete. 

  • The ability to make wise choices or decisions. 

slip of the tongue

noun
  • A mistake in speech. 

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