who carries his flag on the main-mast. A landlord or publican wearing a blue apron, as was formerly the custom among gentlemen of that vocation.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
addle plot * admiral of the narrow seasNathan Bailey's 1721 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes