Green’s Dictionary of Slang

1. an arm; thus of direction, ‘hand side’.

1857		‘Ducange Anglicus’ Vulgar Tongue.
1858		A. Mayhew Paved with Gold 70: ‘Stand back! [...] and leave the kid alone, or I’ll put out my Chalk Farm (my arm) and give you a rap with my Oliver Twist (fist) over your I suppose (nose) that’ll flatten your chevy chase (face) for you!’ he added, menacingly, between his teeth, as he shook his clenched hand in the air.
1864, 1867, 1870		Hotten Sl. Dict.
1881		Trumble Sl. Dict. (1890).
1895		Mirror of Life 27 July 14/2: But what a change came o'er the scene; / His Chalk Farm outward shot, And Long Ned's bushel caught the blow, / And caught it rather hot.
1900–10		Stephens & O’Brien Materials for a Dict. of Aus. Sl. [unpub. ms.] 140: ‘Screw the umpcha [sic] on the left chalk,’ look at the chump on your left hand.
1921		N&Q 12 Ser. IX 345: Chalk-Farm. One’s arm.
1932		‘P.P.’ Rhy. Sl.
1943		M. Harrison Reported Safe Arrival 30: Ole Blanco ’adn’t got muck-all on his chalk-farms.
1960		J. Franklyn Dict. of Rhy. Sl.
1969		S.T. Kendall Up the Frog 20: On ’is Chalk Farm is a Cousin Ella. ‘In case it starts to France an’ Spain,’ ’e sez.
1977		D. Powis Signs of Crime 177: Chalk (Farm) Arm (London district).
1981		P. Wright Cockney Dialect and Sl. 105: Chalk Farm ‘arm’.
2001		M. Coles Bible in Cockney 37: When they met, Joseph threw ’is chalks around his dad.

2. harm.

1960

J. Franklyn Dict. of Rhy. Sl.