additive inverse vs witherward

additive inverse

noun
  • The inverse with respect to addition; the opposite. 

witherward

noun
  • Opposite; adversity, opposition; hostility 

adv
  • Contrary to, against. 

adj
  • Adverse, contrary. 

  • at the witherward side of the year 

  • Opposite, opposing; hostile. 

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