discard vs weed out

discard

verb
  • To throw away, to reject. 

  • To make a discard; to throw out a card. 

  • To dismiss from employment, confidence, or favour; to discharge. 

noun
  • A temporary variable used to receive a value of no importance and unable to be read later. 

  • Anything discarded. 

  • A discarded playing card in a card game. 

weed out

verb
  • to remove unwanted elements from a group 

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