More about legerdemain
There are about 50 spellings in Middle English for (modern) legerdemain. The English word most likely comes from a Middle French phrase leger de main “light of hand,” which is unfortunately unrecorded. Middle French has two similar idioms meaning “to be dexterous”: estre ligier de sa main, literally “to be light of his hand” and avoir la main legiere, literally “to have the light hand.” In English, legerdemain first meant “skill in conjuring, sleight of hand” and acquired the sense “trickery, artful deception” in the 16th century. Legerdemain entered English in the 15th century.