catnap vs sleepytime

catnap

noun
  • A brief, light sleep, usually during the daytime. 

verb
  • To take a catnap (short sleep or nap). 

  • To kidnap a cat. 

sleepytime

noun
  • The time to sleep 

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