detachment vs nonchalance

detachment

noun
  • Indifference to the concerns of others; disregard; nonchalance; aloofness. 

  • A permanent unit organized for special duties. 

  • The state of being detached or disconnected; insulation. 

  • The separation of a military unit from the main body for a particular purpose or special mission. 

  • The unit so dispatched. 

  • The action of detaching; separation. 

  • Absence of bias; impartiality; objectivity. 

  • Any smaller portion of a main body separately employed. 

nonchalance

noun
  • Indifference, unconcern; carelessness; coolness; disregard, detachment. 

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