heated or vehement in spirit, enthusiasm, etc.: a fervid orator.
burning; glowing; intensely hot.
Origin of fervid
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
1590s, from Latin fervidus "glowing, burning; vehement, fervid," from fervere "to boil, glow" (see brew (v.)). Figurative sense of "impassioned" is from 1650s. Related: Fervidly.
Online Etymology Dictionary, © 2010 Douglas Harper