The Collaborative International Dictionary of English v.0.48:

Exhilaration \Ex*hil`a*ra"tion\, n. [L., exhilaratio.]
   1. The act of enlivening the spirits; the act of making glad
      or cheerful; a gladdening.
      [1913 Webster]

   2. The state of being enlivened or cheerful.
      [1913 Webster]

            Exhilaration hath some affinity with joy, though it
            be a much lighter motion.             --Bacon.

   Syn: Animation; joyousness; gladness; cheerfulness; gayety;
        hilarity; merriment; jollity.
        [1913 Webster]

WordNet (r) 3.0 (2006):

exhilaration
    n 1: the feeling of lively and cheerful joy; "he could hardly
         conceal his excitement when she agreed" [syn:
         exhilaration, excitement]