attenuate vs underscore

attenuate

adj
  • Gradually tapering into a petiole-like extension toward the base. 

verb
  • To reduce the amplitude of an electrical, radio, or optical signal. 

  • To weaken. 

  • To reduce in size, force, value, amount, or degree. 

  • To become thin or fine; to grow less. 

  • To rarefy. 

  • (of a beer) To become less dense as a result of the conversion of sugar to alcohol. 

  • To reduce the virulence of a bacterium or virus. 

  • To make thinner, as by physically reshaping, starving, or decaying. 

underscore

noun
  • An underline; a line drawn or printed beneath text; the character _. 

  • A piece of background music. 

verb
  • To emphasize or draw attention to. 

  • To underline; to mark a line beneath text. 

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