brio

brio \BREE-oh\, noun:

Enthusiastic vigor; vivacity; liveliness; spirit.

Though my judgment was no doubt affected by all the wine we'd consumed, I remember being elated by our performance that night: our inspired spur-of-the-moment dialogue, the actors fleshing out their roles with such brio.
-- Gail Godwin, Evensong

For him, life must be a party, a ball, an endless carnival. Each person must invent a role for himself and play it with brio.
-- Lydia Flem, Casanova: The Man Who Really Loved Women (translated by Catherine Temerson)

The Internet has always been home to plenty of unvarnished brio.
-- Timothy L. O'Brien, "Corporate Love Letters: Youstink.Com", New York Times, April 4, 1999

Brio is Italian, from Spanish brio or Provençal briu, both of Celtic origin.