regret vs wail

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. 

wail

verb
  • To lament; to bewail; to grieve over. 

  • To make a noise like mourning or crying. 

  • To weep, lament persistently or bitterly. 

  • To cry out, as in sorrow or anguish. 

  • To perform with great liveliness and force. 

noun
  • A sound made by emergency vehicle sirens, contrasted with "yelp" which is higher-pitched and faster. 

  • Any similar sound as of lamentation; a howl. 

  • A prolonged cry, usually high-pitched, especially as of grief or anguish. 

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