hairline vs shallow

hairline

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. 

adj
  • very thin, as thin as a hair 

shallow

noun
  • A fish, the rudd. 

  • A costermonger's barrow. 

  • A shallow portion of an otherwise deep body of water. 

adj
  • Not steep; close to horizontal. 

  • Not far forward, close to the net. 

  • Having little depth; significantly less deep than wide. 

  • Not intellectually deep; not penetrating deeply; simple; not wise or knowing. 

  • Concerned mainly with superficial matters. 

  • Extending not far downward. 

  • Lacking interest or substance. 

verb
  • To make or become less deep. 

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