moan vs regret

moan

noun
  • a low, mournful cry of pain, sorrow or pleasure 

verb
  • To complain; to grumble. 

  • To say in a moan, or with a moaning voice. 

  • To grieve. 

  • To make a moan or similar sound. 

regret

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. 

verb
  • 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. 

  • To feel sorry about (any thing). 

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