Source : Webster's Revised Unabridged Dictionary (1913)

Tasteful \Taste"ful\, a.
   1. Having a high relish; savory. ``Tasteful herbs.'' --Pope.

   2. Having or exhibiting good taste; in accordance with good
      taste; tasty; as, a tasteful drapery. -- {Taste"ful*ly},
      adv. -- {Taste"ful*ness}, n.

Source : WordNet®

tastefulness
     n : elegance indicated by good taste [ant: {tastelessness}]