damp vs dampness

damp

noun
  • Moisture; humidity; dampness. 

  • A gaseous product, formed in coal mines, old wells, pits, etc. 

adj
  • In a state between dry and wet; moderately wet; moist. 

  • Despondent; dispirited, downcast. 

verb
  • To suppress vibrations (mechanical) or oscillations (electrical) by converting energy to heat (or some other form of energy). 

dampness

noun
  • Moderate humidity; moisture; moistness; the state or quality of being damp. 

  • The degree to which something is damp or moist. 

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