Mountain climbed by Moses (5)
I believe the answer is:
'mountain climbed by moses' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sinai that I've seen before include "Mountain in Egypt" , "Part of 10 [EGYPT]" , "Deserted area" , "Mountain source of Mosaic Law" , "Biblical mount" .)