brush-off vs castoff

brush-off

noun
  • An abrupt rebuff, a snub or curt rejection, a disdainful dismissal. 

castoff

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

adj
  • discarded, rejected. 

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