Small flute used by Sufi fellowship (4)
I believe the answer is:
fife
'small flute' is the definition.
(I've seen this in another clue)
'used by sufi fellowship' is the wordplay.
'used by' indicates a hidden word.
'FIFE' is hidden within 'sufi fellowship'.
(Other definitions for fife that I've seen before include "Small shrill flute" , "What's played" , "part of Scotland?" , "Type of flute: Scottish council area" , "Kind of small flute" .)