Green’s Dictionary of Slang

1. to feel, to handle; to grope a woman.

1741		Canting Academy, or the Pedlar’s-French Dict. 117: To feel a Woman where they generally have a fancy To fam.
1812		Vaux Vocab. of the Flash Lang.

2. (UK und.) to pick a pocket.

1850

Man of Pleasure’s Illus. Pocket-book n.p.: ‘If I can't pinch a skin or a reader, I can fam a cly for a chance’.