big cat vs housecat

big cat

noun
  • Used other than figuratively or idiomatically: see big, cat. 

  • Any large feline animal, especially one of the Panthera genus, including tigers, lions, jaguars and leopards. 

housecat

noun
  • A pet cat that is not allowed outside 

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