sleep in vs snooze

sleep in

verb
  • To sleep late; to go on sleeping past one's customary or planned hour. 

  • Used other than figuratively or idiomatically: see sleep, in. 

snooze

verb
  • To sleep, especially briefly; to nap, doze. 

  • To pause; to postpone for a short while. 

noun
  • Something boring. 

  • The snooze button on an alarm clock. 

  • A brief period of sleep; a nap. 

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