Supernatural presence moaned when disturbed (6)
I believe the answer is:
daemon
'supernatural presence' is the definition.
'moaned when disturbed' is the wordplay.
'when disturbed' indicates anagramming the letters.
'moaned' with letters rearranged gives 'DAEMON'.
(Other definitions for daemon that I've seen before include "Spirit in ancient Greek belief" , "Evil spirit" , "guardian spirit" .)