adjective (a)

• not forming an essential part of a thing or arising or originating from the outside(adj.all)

  Example:
  Extrinsic evidence.
  An extrinsic feature of the new building.
  That style is something extrinsic to the subject.
  Looking for extrinsic aid.
  

  Antonym:
  intrinsic, intrinsical
  

  source: wordnet30
• Not contained in or belonging to a body; external; outward; unessential; -- opposed to intrinsic.(adjective)

  source: webster1913