double-barrelled

Short definition from Wiktionary

Adjective

1. 1
   Used other than figuratively or idiomatically: see double, barrelled. Having two barrels, as a gun.
2. 2
   Twofold, having a double purpose or nature.
3. 3
   Having two separate parts, often adjoined by a hyphen (or sometimes a space).
4. 4
   Forceful, powerful (like a double-barrelled shotgun).