fatigues vs khakis

fatigues

noun
  • Military clothing worn when doing menial tasks. 

  • Menial duties, especially as punishment. 

khakis

noun
  • A khaki uniform of pants (trousers) or shorts, shirt, and hat or other head covering such as a turban. 

  • Khaki-coloured/colored cotton trousers (pants). 

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