A house painter, who occasionally paints or anoints posts. Knight of the post; a false evidence, one ready to swear any thing for hire. From post to pillar; backwards and forwards.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Post Master General * Postilion of the GospelNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes