apropos vs as far as

apropos

prep
  • Regarding or concerning. 

adj
  • Of an appropriate or pertinent nature. 

  • by the way, incidental 

adv
  • To the purpose; appropriately. 

  • By the way. 

  • Timely; at a good time. 

as far as

prep
  • With respect to; as relates to. 

  • Used other than figuratively or idiomatically: see as, far, as. 

conj
  • To the degree or extent that. 

  • Used other than figuratively or idiomatically: see as, far, as. 

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