Do you know ghouls from goblins and ghosts?
1650s, "dry, parched," from French aride (15c.) or directly from Latin aridus "dry, arid, parched," from arere "to be dry," from PIE root *as- "to burn, glow" (see ash (n.1)). Figurative sense of "uninteresting" is from 1827. Related: Aridly.