espial vs onlook

espial

noun
  • An act of noticing or observing. 

  • The fact of noticing or observing; a discovery. 

onlook

noun
  • The act of looking on (something); observation. 

  • One's perspective or outlook. 

  • That which is looked at, regarded, or considered. 

verb
  • To look on or look at; watch; observe; view; regard. 

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