hairline vs mental

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 

mental

noun
  • A plate or scale covering the mentum or chin of a fish or reptile. 

adj
  • Occurring or experienced in the mind. 

  • Of or relating to telepathic or mind-reading powers. 

  • Of, relating to, or being intellectual as contrasted with overt physical activity. 

  • Of or relating to the chin or median part of the lower jaw, genial. 

  • Relating to the mind, its activity, or its products as an object of study. 

  • Relating to spirit or idea as opposed to matter. 

  • Enjoyable or fun, especially in a frenetic way. 

  • Of or relating to the chinlike or liplike structure. 

  • Of, relating to, or affected by a psychiatric disorder. 

  • Of or relating to intellectual as contrasted with emotional activity. 

  • Intended for the care or treatment of persons affected by psychiatric disorders. 

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