·noun A stupid, blundering fellow.
II. Blunderbuss ·noun A short gun or firearm, with a large bore, capable of holding a number of balls, and intended to do execution without exact aim.
A short gun, with a wide bore, for carrying slugs; also a stupid, blundering fellow. ...
Dictionary of The Vulgar Tongue by Francis Grose
A short fire-arm, with a large bore and wide mouth, to scatter a number of musket or pistol bullets ...
The Sailor's Word-Book