A nosegay. I shall see you ride backwards up Holborn-hill, with a book in one hand, and a posey in t’other; i.e. I shall see you go to be hanged. Malefactors who piqued themselves on being properly equipped for that occasion, had always a nosegay to smell to, and a prayer book, although they could not read.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
porridge island * posse mobilitatisNathan Bailey's 1721 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes