Astrology and (formerly) Astronomy. That is descending towards or below the horizon; (of a planet) passing to where it has less astrological…

Sinking below or nearing the horizon; said of the sun or other heavenly body, its light, etc.

= occiduous, adj.

Going down, setting; relating to the setting of a celestial object.

Of or relating to descent or descension.

Declining.