castoff vs inept

castoff

adj
  • discarded, rejected. 

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

inept

adj
  • Unfit; unsuitable. 

  • Not able to do something; not proficient; displaying incompetence. 

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