discard vs mull over

discard

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. 

verb
  • To throw away, to reject. 

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

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

mull over

verb
  • To think deeply about something; to ponder, deliberate or ruminate. 

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