The Greek adjective anydros (ἄνυδρος) means "waterless" or "without water" — from a- (negative) + hydōr (water). It describes places or conditions that are parched and desolate — literally lacking water. In the New Testament, the word appears in descriptions of demonic dwelling places and in condemnations of false teachers. The image of waterlessness resonates with the Old Testament desert wilderness as a place of testing and spiritual danger.
The New Testament uses anydros to describe the haunt of unclean spirits (Matthew 12:43; Luke 11:24) — when a demon is cast out, it "passes through waterless [anydros] places seeking rest." The desert/wilderness is the realm of spiritual desolation, the territory between ordered life and demonic chaos. Jude 12 and 2 Peter 2:17 use anydros for false teachers who are "waterless clouds" — they appear to bring rain (refreshment, nourishment) but deliver nothing. The image is devastating: a cloud that produces no rain in a land that desperately needs water is worse than no cloud at all, because it raises and then crushes hope. False teaching is spiritually arid: it promises life but produces nothing that sustains.