hairline vs rare

hairline

adj
  • very thin, as thin as a hair 

noun
  • A fishing line made from hair. 

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

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

  • A very thin fissure. 

rare

adj
  • Thin; of low density. 

  • Very uncommon; scarce. 

  • Particularly of meat, especially beefsteak: cooked very lightly, so the meat is still red. 

  • Good; enjoyable. 

verb
  • To rear, bring up, raise. 

  • To rear, rise up, start backwards. 

noun
  • A scarce or uncommon item. 

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