Hunter constellation (5)
I believe the answer is:
orion
'hunter constellation' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for orion that I've seen before include "Greek hunter became a constellation" , "Constellation in the form of a belt" , "He hunted" , "His belt is in the heavens" , "Great hunter of Greek legend and a constellation" .)