The Collaborative International Dictionary of English v.0.48:

Expressive \Ex*press"ive\, a. [Cf. F. expressif.]
   1. Serving to express, utter, or represent; indicative;
      communicative; -- followed by of; as, words expressive of
      his gratitude.
      [1913 Webster]

            Each verse so swells expressive of her woes.
                                                  --Tickell.
      [1913 Webster]

   2. Full of expression; vividly representing the meaning or
      feeling meant to be conveyed; significant; emphatic; as,
      expressive looks or words.
      [1913 Webster]

            You have restrained yourself within the list of too
            cold an adieu; be more expressive to them. --Shak.
      [1913 Webster]

            Through her expressive eyes her soul distinctly
            spoke.                                --Littelton.
      -- Ex*press"ive*ly,adv. -- Ex*press"ive*ness,n.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

expressiveness \ex*press"ive*ness\ n.
   the quality of being expressive.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

expressiveness
    n 1: the quality of being expressive