leg·er·de·main 
(l
ĕj
′ər-d
ə-m
ān
)
n.1. Sleight of hand.
2. Deceitful cleverness; trickery: financial legerdemain.
[Middle English legerdemayn, from Old French leger de main : leger, light (from Vulgar Latin *leviārius, from Latin levis; see legwh- in the Appendix of Indo-European roots) + de, of (from Latin dē; see DE-) + main, hand; see MORTMAIN.]