duplicity
n.
early 15c., from Old French duplicite (13c.), from Late Latin duplicitatem (nominative duplicitas) "doubleness," in Medieval Latin "ambiguity," noun of quality from duplex (genitive duplicis) "twofold." The notion is of being "double" in one's conduct (compare Greek diploos "treacherous, double-minded," literally "twofold, double").
〔蒋〕[du=two二，-icity表示性质] 二重性，口是心非，表里不一
〔蒋〕[plic=fold折，重叠，-ity表示性质] 二重性，表里不一，口是心非