A holiday most religiously observed by journeymen shoemakers, and other inferior mechanics. a profanation of that day, by working, is punishable by a line, particularly among the gentle craft. An Irishman observed, that this saint’s anniversary happened every week.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Saint Luke’s Bird * SalNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes