monotone vs otiose

monotone

adj
  • Being, or having the salient properties of, a monotone function. 

  • Having a single unvaried pitch. 

verb
  • To speak in a monotone. 

noun
  • A piece of writing in one strain throughout. 

  • A single unvaried tone of speech or a sound. 

otiose

adj
  • Having no reason for being (raison d’être); having no point, reason, or purpose. 

  • Done in a careless or perfunctory manner. 

  • Having no effect. 

  • Reluctant to work or to exert oneself. 

  • Of a person, possessing a bored indolence. 

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