castoff vs frustrate

castoff

adj
  • discarded, rejected. 

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

frustrate

adj
  • ineffectual; useless; fruitless. 

verb
  • To cause stress or annoyance. 

  • To disappoint or defeat; to vex by depriving of something expected or desired. 

  • To hinder or thwart. 

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