effervescent

effervescent \ef-er-VES-uhnt\, adjective:

1. High-spirited; vivacious; lively.
2. Effervescing; bubbling.

One of them was a thickset young man who played doggedly without speaking, the other was an effervescent young man with white eyebrows and a nervous manner.
-- James Joyce, Stephen Hero

Bobbing up and down, for a few seconds, like an apple in a bowl of toddy, he, at length, finally disappeared amid the whirlpool of foam which, in the already effervescent liquor, his struggles easily succeeded in creating.
-- Edgar Allan Poe, King Pest

That night, when Jennifer and I go out to dinner, she is effervescent with plans for our future.
-- Isaac Asimov, Science Fiction Magazine, Volume 8, 1984

Effervescent originated as a French verb in the 1650s meaning, 'the action of boiling up' (as in water), though it did not assume its figurative meaning relating to personality until 1748.