let on vs reveal

let on

verb
  • to reveal or indicate, especially unintentionally or against one's wishes 

  • Used other than figuratively or idiomatically: see let, on. 

reveal

verb
  • To uncover; to show and display that which was hidden. 

  • To communicate that which could not be known or discovered without divine or supernatural instruction. 

noun
  • The outer side of a window or door frame. 

  • A revelation; an uncovering of what was hidden in the scene or story. 

How often have the words let on and reveal occurred in a corpus of books? (source: Google Ngram Viewer )