circa vs nigh

circa

prep
  • Approximately, about, around (typically in relation to time) 

nigh

prep
  • near; close to 

verb
  • to draw nigh (to); to approach; to come near 

adv
  • Almost, nearly. 

adj
  • Not remote in degree, kindred, circumstances, etc.; closely allied; intimate. 

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