lament vs regret

lament

noun
  • An expression of grief, suffering, sadness or regret. 

  • A song expressing grief. 

verb
  • To express grief; to weep or wail; to mourn. 

  • To feel great sorrow or regret; to bewail. 

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 lament and regret occurred in a corpus of books? (source: Google Ngram Viewer )