jail vs let off

jail

noun
  • In dodgeball and related games, the area where players who have been struck by the ball are confined. 

  • Confinement in a jail. 

  • A kind of sandbox for running a guest operating system instance. 

  • A place or institution for the confinement of persons held against their will in lawful custody or detention, especially (in US usage) a place where people are held for minor offenses or with reference to some future judicial proceeding. 

  • The condition created by the requirement that a horse claimed in a claiming race not be run at another track for some period of time (usually 30 days). 

verb
  • To imprison. 

let off

verb
  • To forgive and not punish. 

  • To cause to explode or come out; to release. 

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