grief vs mourning

grief

noun
  • Cause or instance of sorrow or pain; that which afflicts or distresses; trial. 

  • Suffering, hardship. 

  • Emotional pain, generally arising from misfortune, significant personal loss, bereavement, misconduct of oneself or others, etc.; sorrow; sadness. 

verb
  • To deliberately harass and annoy or cause grief to other players of a game in order to interfere with their enjoyment of it; especially, to do this as one’s primary activity in the game. 

mourning

noun
  • The act of expressing or feeling sorrow or regret; lamentation. 

  • The traditional clothes worn by those who mourn (in Western societies, typically coloured black). 

  • Feeling or expressing sorrow over someone's death. 

  • Drapes or coverings associated with mourning. 

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