Definition of double-barrelled:
(adj) :
Twofold, having a double purpose or nature.
(adj) :
(of names) Having two separate parts, often adjoined by a hyphen (or sometimes a space).
(adj) :
(figurative) Forceful, powerful (like a double-barrelled shotgun).
(adj) :
Used other than figuratively or idiomatically: see double, barrelled. Having two barrels, as a gun.