Duplicity could mean several things, the latin base PLIC means "to fold; to tangle." but the real definition is
1: contradictory doubleness of thought, speech, or action ; especially : the belying of one's true intentions by deceptive words or action2: the quality or state of being double or twofold3: the technically incorrect use of two or more distinct items (as claims, charges, or defenses) in a single legal action
From www.m-w.com