Green’s Dictionary of Slang

(UK Und.) a trouser pocket.

1821		D. Haggart Autobiog. 9: I got the first dive at his keek cloy, and I was so eager on my prey, that I pulled out the pocket along with the money. [Ibid.] 12: The keek cloy is easily picked. If the notes are in the long fold, just tip them the forks; but if there is a purse or open money in the case, you must link it.
1897		C. Whibley ‘The Switcher’ A Book of Scoundrels 211: ‘The keek-cloy,’ he wrote, in his hints to young sportsmen, ‘is easily picked.’.