stratagem vs subterfuge

stratagem

noun
  • Military deception or artifice. 

  • Cunning and artifice in general. 

  • A tactic or artifice designed to gain the upper hand, especially one involving underhanded dealings or deception. 

  • Specifically, such a tactic or artifice in military operation. 

subterfuge

noun
  • An indirect or deceptive device or stratagem; a blind. Refers especially to war and diplomatics. 

  • Deception; misrepresentation of the true nature of an activity. 

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