low-pressure vs nonchalant

low-pressure

adj
  • The opposite of high-pressure, defined by contrast. 

nonchalant

adj
  • Indifferent; unconcerned; behaving as if detached. 

  • Casually calm and relaxed. 

How often have the words low-pressure and nonchalant occurred in a corpus of books? (source: Google Ngram Viewer )