Stinking, rammish, ill-flavoured; also strong, great. A rank knave; a rank coward: perhaps the latter may allude to an ill savour caused by fear.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Rangling * Rank RiderNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes