adequate vs passable

adequate

adj
  • Equal to or fulfilling some requirement. 

det
  • A sufficient amount of; enough. 

passable

adj
  • Tolerable; adequate; no more than satisfactory. 

  • able to "pass", or be accepted as a member of a race, sex or other group to which society would not otherwise regard one as belonging. 

  • That may be passed or traversed. 

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