sb. slang. [f. FLAT sb.3 + -Y1.] One who is ignorant of the methods of professional thieving; a flat; also comb.: flatty-ken (see quot.).
1851. Mayhew, Lond. Labour (1861), I. 218. They betray to the ‘flatties’ (natives) all their profits and proceedings. Ibid. (1851), I. 243. Some take up their abode in what they call ‘flatty-kens,’ that is, houses the landlord of which is not ‘awake’ or ‘fly’ to the ‘moves’ and dodges of the trade.
