sober vs surd

sober

adj
  • Not drunk; not intoxicated. 

  • Poor; feeble. 

  • Not given to excessive drinking of alcohol. 

  • Moderate; realistic; serious; not playful; not passionate; cool; self-controlled. 

  • Not under the influence of any recreational drug. 

  • Dull; not bright or colorful. 

  • Given to excessive drinking of alcohol, but having made a conscious decision to abstain from it. 

  • Subdued; solemn; grave. 

verb
  • To make or become sober. 

  • To moderate one's feelings. 

  • To overcome or lose a state of intoxication. 

surd

adj
  • unvoiced; voiceless 

  • Involving surds, or irrational numbers; not capable of being expressed in rational numbers. 

noun
  • An irrational number, especially one expressed using the √ symbol. 

  • A voiceless consonant. 

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