In astrology, the fall of a planet is the sign or "zoidion" which is opposite that planet's sign of exaltation.
Planets in ''fall'' are uncomfortable and weak, having much less power to assert their own identity. A planet's "fall" is the sign that seems to resist the planet's nature the most, resulting in impasse & failure. ''Fall'' is a form of debilitated essential dignity which is among the most ancient of all astrological concepts still in use, having its origin in Mesopotamian omens, before the beginning of horoscopic astrology.