despair vs regret

despair

verb
  • To cause to despair. 

  • To be hopeless; to have no hope; to give up all hope or expectation. 

noun
  • That which causes despair. 

  • Loss of hope; utter hopelessness; complete despondency. 

  • That which is despaired of. 

regret

verb
  • To feel sorry about (any thing). 

  • To feel sorry about (a thing that has or has not happened), afterthink: to wish that a thing had not happened, that something else had happened instead. 

noun
  • Emotional pain on account of something done or experienced in the past, with a wish that it had been different; a looking back with dissatisfaction or with longing. 

  • The amount of avoidable loss that results from choosing the wrong action. 

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