antithesis vs polar opposite

antithesis

noun
  • A proposition that is the diametric opposite of some other proposition. 

  • A device by which two contrasting ideas are juxtaposed in parallel form; a figure of speech arranged in this manner 

polar opposite

noun
  • The complete opposite, opposite in every way. 

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