surd vs untold

surd

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

  • unvoiced; voiceless 

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

  • A voiceless consonant. 

untold

adj
  • Not numbered or counted. 

  • Not told; not related; not revealed; secret. 

  • Not able to be counted, measured, told, expressed in words, or described; extremely large in scale, number, quantity, suffering, damage, etc.; uncountable, unmeasurable, immeasurable, indescribable, inexpressible. 

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