Do you know ghouls from goblins and ghosts?
1590s, from Middle French aridité or directly from Latin ariditatem (nominative ariditas) "dryness," from aridus (see arid). The Latin word was used figuratively of unadorned styles as well as stingy men.
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.