ailing vs hairline

ailing

noun
  • An ailment. 

adj
  • Sickly; sick; ill; unwell. 

hairline

noun
  • The line along one's forehead where hair starts growing. 

  • A fishing line made from hair. 

  • A very thin line in writing, drawing, or typography. 

  • A very thin fissure. 

adj
  • very thin, as thin as a hair 

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