Earth's rocky orbiter (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
moon
(Other definitions for moon that I've seen before include "who headed a religious 29 [CULT]" , "Reveal rear" , "It may be full, half or crescent" , "Earthly satellite" , "Heavenly body < exemplified in Titania?" .)