Green tower rising above a hotel (6)
I believe the answer is:
moolah
'green' is the definition.
(I've seen this in another clue)
'tower rising above a hotel' is the wordplay.
'tower' becomes 'loom' (synonyms).
'rising' shows that the letters should be reversed in order (letters written upwards in a down clue).
'above' says to put letters next to each other (in a down clue, some letters go above others).
'hotel' becomes 'h' (phonetic alphabet).
'loom' backwards is 'mool'.
'mool'+'a'+'h'='MOOLAH'
(Other definitions for moolah that I've seen before include "dosh" , "bread" , "money on the streets" .)