Empower leaderless men on revolutionary island (6)
I believe the answer is:
enable
'empower' is the definition.
(thesaurus)
'leaderless men on revolutionary island' is the wordplay.
'leaderless' means to remove the first letter.
'on' is a charade indicator (letters next to each other).
'revolutionary' says the letters should be written backwards.
'island' becomes 'elba' (I've seen this before**).
'elba' in reverse letter order is 'able'.
'men' with its initial letter removed is 'en'.
'en'+'able'='ENABLE'
(Other definitions for enable that I've seen before include "Make it possible for someone to do something" , "Permit or facilitate" , "Empower" , "Render capable" , "Capacitate" .)