dead calm vs purely

dead calm

adj
  • Completely still with no waves and no wind. 

noun
  • The condition of a perfectly flat sea with no waves and no wind. 

purely

adj
  • without physical adulterants; with no admixture 

adv
  • Chastely, innocently; in a sinless manner, without fault. 

  • Wholly; really, completely. 

  • Solely; exclusively; merely, simply. 

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