Synonyms for Enthusiastic:

adj.

active (adjective)
lively.
ambitious (adjective)
inspired.
cheerful (adjective)
sanguine.
enthusiastic (adjective)
wholehearted, spirited, excited, mad about something, ardent, devoted, eager, zealous, enthused, motivated, fanatical, hooked, born-again, fervent.
excitable (adjective)
mercurial, excitable.
excited (adjective)
keyed up, psyched.
hopeful (adjective)
aspiring.
interested, excited (adjective)
fanatical, concerned, animated, vigorous, earnest, rabid, thrilled, fervid, eager, athirst, exuberant, ardent, pleased, passionate, wholehearted, fascinated, avid, gung ho, zealous, ebullient, lively, crazy about, fervent, hearty, willing, keyed up, spirited, agog, warm, devoted.
lively (adjective)
lively, active, alert, animated, vital, brisk, vigorous, mettlesome.
overenthusiastic (adjective)
fanatical.
sensitive (adjective)
excitable.
vigorous (adjective)
fiery, emphatic, prolific, mettlesome, afire, animated, potent, ardent, eager, vigorous, fervent, peppy, puissant, zealous, lusty, industrious, sprightly, lively, excited, spirited, ablaze, full-blooded, passionate, burning, hearty, active, strong, exuberant, strenuous, virile, zestful, energetic, earnest, zippy, impassioned, powerful, agitated, frisky.

n.

nuts, mad, concern. enthusiastic (noun)
ardent, great, eager, glowing, evangelical, evangelistic, warm, overenthusiastic, zealous, crazy, avid, gung ho.

Other synonyms:

crazy about, interested, ambitious. nuts. mad. exuberant
ebullient.
fanatical
rabid.
out of breath
breathless.
overzealous
overeager.
sentimental
gushing.
unwearied
tireless.
yearning
Desiring.
zealous
willing.

Usage examples for enthusiastic

  1. When they first entered Switzerland she was very enthusiastic and declared her intention of climbing up all the mountains, and going through all the passes. – Can You Forgive Her? by Anthony Trollope
  2. Of course, he is enthusiastic on the subject. – Mr. Hogarth's Will by Catherine Helen Spence