constantly vs nonstop

constantly

adv
  • In a constant manner; occurring continuously; persistently. 

  • In an unchangeable or invariable manner; in every case. 

  • Recurring regularly. 

nonstop

adv
  • Without stopping; without interruption or break 

noun
  • A linguistic sound that is not a stop; a continuant. 

  • A convenience store in parts of Europe, open 24 hours a day. 

  • A nonstop journey, especially a nonstop flight. 

adj
  • Without stopping; without interruption or break. 

  • Describing a point mutation within a stop codon that causes the continued translation of an mRNA strand. 

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