legerdemain

From Middle English legerdemeyn, lechardemane, from Old French léger de main (literally “light of hand”), a phrase that meant “dexterous, skillful at fooling others (especially through sleights of hand)”, which was however treated as a noun when it was borrowed by late Middle English. The Modern French descendant léger de main of the Old French phrase is archaic but still sometimes found in older literature and simply means “skillful” without any connotation of sleight of hand.

来源：wiktionary