Dances with British revolutionaries (6)
I believe the answer is:
rebels
'revolutionaries' is the definition.
(I know this)
'dances with british' is the wordplay.
'dances' becomes 'reels' (reel is a kind of dance).
'with' means one lot of letters goes inside another.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'reels' enclosing 'b' is 'REBELS'.
(Other definitions for rebels that I've seen before include "Insurgents, mutineers" , "Resists" , "They resist authority, perhaps with force" .)