A jocular name, or term of reproach, to one who stops the circulation of the glass by preaching over his liquor; as it is said was done by a parson of that name whose cellar was under his pulpit.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Parson’s Journeyman * PartialNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes