fervid

fervid \FUR-vid\, adjective:

1. Heated or vehement in spirit, enthusiasm, etc.
2. Burning; glowing; intensely hot.

Over the last week, the Cubs opened their home season at Wrigley Field, and the city's Lyric Opera was presenting Richard Wagner's four-opera "Ring des Nibelungen," which meant that two of the world's most fervid fan bases were simultaneously encamped on opposite sides of the Chicago River.
-- Bruce Weber, "Take Me Out to the Opera: In Chicago, a Fan Is a Fan", New York Times, April 16, 2009

The words of fire that from his pen
Were flung upon the fervid page,
Still move, still shake the hearts of men,
Amid a cold and coward age.
-- William Cullen Bryant

Fervid comes from Latin fervidus "glowing, burning, vehement," from fervere "to boil, glow." The figurative sense of "impassioned" is from 1656.