fervid (adj.)

1590s, "burning, glowing, hot," from Latin fervidus "glowing, burning; vehement, fervid," from fervere "to boil, glow" (from PIE root *bhreu- "to boil, bubble, effervesce, burn"). Figurative sense of "impassioned" is from 1650s. Related: Fervidly; fervidness.