eat away at vs flay

eat away at

verb
  • To cause to feel uneasy, troubled, worried, guilty, or vexed; to bother about something. 

  • To erode. 

  • To consume or use up, erode or wear away gradually. 

flay

verb
  • To frighten; scare; terrify. 

  • To cause to fly; put to flight; drive off (by frightening). 

  • To be fear-stricken. 

  • To strip the skin off; to skin. 

  • To lash or whip. 

noun
  • A fright; a scare. 

  • Fear; a source of fear; a formidable matter; a fearsome or repellent-looking individual. 

How often have the words eat away at and flay occurred in a corpus of books? (source: Google Ngram Viewer )