The Collaborative International Dictionary of English v.0.48:

Ebullient \E*bul"lient\, a. [L. ebulliens, -entis, p. pr. of
   ebullire to boil up, bubble up; e out, from + bullire to
   boil. See 1st Boil.]
   Boiling up or over; hence, manifesting exhilaration or
   excitement, as of feeling; effervescing. "Ebullient with
   subtlety." --De Quincey.
   [1913 Webster]

         The ebullient enthusiasm of the French.  --Carlyle.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ebullient
    adj 1: joyously unrestrained [syn: ebullient, exuberant,
           high-spirited]

Moby Thesaurus II by Grady Ward, 1.0:

125 Moby Thesaurus words for "ebullient":
   active, activist, activistic, agog, alive, animated, aquiver,
   ardent, aroused, atingle, atwitter, baking, beaten, blebby,
   blistered, blistering, blistery, boiling, bouncing, bouncy, brash,
   breezy, brisk, broiling, bubbling, bubbly, burbling, burbly,
   burning, burning hot, bursting, canicular, carbonated,
   carried away, chiffon, chipper, effervescent, energetic, excited,
   exhilarated, feverish, fired, fizzy, flushed, frisky, full of go,
   full of life, full of pep, grilling, heated, high, high-spirited,
   hopped up, hot, hot as fire, hot as hell, impassioned, inflamed,
   keyed up, lathered up, like a furnace, like an oven, live, lively,
   manic, mercurial, militant, moved, overheated, overwarm, parching,
   peppy, perky, pert, piping hot, puffed, quicksilver,
   ready to burst, red-hot, roasting, roused, scalding, scorching,
   searing, seething, simmering, sizzling hot, smacking, smoking hot,
   snappy, souffle, souffleed, spanking, sparkling, spirited,
   sprightly, spry, spumescent, steamed up, stimulated, stirred,
   stirred up, sudorific, sweating, sweaty, sweltering, sweltry,
   thrilled, tingling, tingly, toasting, torrid, turned-on, vesicant,
   vesicated, vesicatory, vesicular, vivacious, whipped, whipped up,
   white-hot, worked up, wrought up, yeasty, zingy