Diver taking part in quelling rebellion (5)
I believe the answer is:
grebe
'diver' is the definition.
(diving bird)
'part in quelling rebellion' is the wordplay.
'part in' indicates a hidden word.
'GREBE' is hidden in the letters of 'quelling rebellion'.
'taking' is the link.
(Other definitions for grebe that I've seen before include "I'll dive in" , "Diving bird which may be crested" , "Small bird that builds floating nests" , "Duck-sized water-bird" , "Freshwater diving bird" .)