accroach vs enslave

accroach

verb
  • To encroach. 

  • To usurp, as jurisdiction or royal prerogatives. 

  • To hook, or draw to oneself as with a hook. 

enslave

verb
  • To make subservient; to strip one of freedom; enthrall. 

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