myriad vs numberless

myriad

adj
  • Great in number; innumerable, multitudinous 

  • Multifaceted, having innumerable elements 

noun
  • A countless number or multitude (of specified things) 

  • Ten thousand; 10,000 

numberless

adj
  • Without number; having too many to count. 

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