Moons around, then advanced, half asleep (9)
I believe the answer is:
somnolent
'half asleep' is the definition.
(thesaurus)
'moons around then advanced' is the wordplay.
'around' indicates anagramming the letters.
'then' is a charade indicator (letters next to each other).
'advanced' becomes 'lent' (money).
'moons' with letters rearranged gives 'somno'.
'somno'+'lent'='SOMNOLENT'
(Other definitions for somnolent that I've seen before include "falling asleep" , "Drowsy - lost on men (anag)" , "Sleepy, drowsy" , "Dozy" , "Comatose" .)