castoff vs extinct

castoff

adj
  • discarded, rejected. 

noun
  • Something that has been rejected or discarded; a reject. 

extinct

adj
  • No longer used; obsolete, discontinued. 

  • No longer active. 

  • No longer in existence; having died out. 

verb
  • To make extinct; to extinguish or annihilate. 

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