oppugnancy vs skirmish

oppugnancy

noun
  • The act of oppugning; opposition; resistance 

skirmish

noun
  • Any minor dispute. 

  • A brief battle between small groups, usually part of a longer or larger battle or war. 

  • A type of outdoor military style game using paintball or similar weapons. 

verb
  • To engage in a minor battle or dispute 

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