The Collaborative International Dictionary of English v.0.48:

Sprightly \Spright"ly\ (-l[y^]), a. [Compar. Sprightlier
   (-l[i^]*[~e]r); superl. Sprightliest.] [See Sprite.]
   Sprightlike, or spiritlike; lively; brisk; animated;
   vigorous; airy; gay; as, a sprightly youth; a sprightly air;
   a sprightly dance. "Sprightly wit and love inspires."
   --Dryden.
   [1913 Webster]

         The sprightly Sylvia trips along the green. --Pope.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sprightly
    adj 1: full of spirit and vitality; "a sprightly young girl"; "a
           sprightly dance"

Moby Thesaurus II by Grady Ward, 1.0:

100 Moby Thesaurus words for "sprightly":
   Attic, active, activist, activistic, agile, alert, alive, animate,
   animated, antic, biting, bouncing, bouncy, breezy, brilliant,
   brisk, bubbly, capersome, cheerful, chipper, clever, coltish,
   droll, ebullient, effervescent, energetic, exuberant, facetious,
   featly, fleet, frisky, frolicsome, full of beans, full of go,
   full of life, full of pep, funny, gamesome, gay, good, graceful,
   hearty, humorous, humorsome, jaunty, jesting, jocose, jocular,
   joking, joky, joshing, keen, keen-witted, light, light-footed,
   live, lively, mercurial, militant, mordant, neat-fingered,
   neat-handed, nimble, nimble-footed, nimble-witted, peart, peppy,
   perky, pert, playful, pointed, pungent, quick-witted, quicksilver,
   rapier-like, rollicking, rollicksome, rompish, salt, salty,
   scintillating, sharp, skittish, smacking, smart, snappy, spanking,
   sparkling, spirited, sportive, spry, sure-footed, vital, vivacious,
   volant, whimsical, witty, zestful, zingy, zippy