Definitions of contrastive:

• adjective:   of words so related that one contrasts with the other

  Example: "`rich' and `hard-up' are contrastive terms"

• adjective:   syntactically establishing a relationship of contrast between sentences or elements of a sentence

  Example: "Disjunctive conjunctions like `but', `or', or `though' serve a contrastive function"

• adjective:   strikingly different; tending to contrast

  Example: "Contrasting (or contrastive) colors"