Deceitfulness in speech or conduct, as by speaking or acting in two different ways to different people concerning the same matter; double-dealing. The politician was accused of duplicity after promising different things to different groups.
The state or quality of having two elements or parts; being twofold or double. The duplicity of the design allowed it to serve both as a table and a storage unit.
Law: the improper joining of two or more distinct offenses or causes of action in a single count of an indictment or pleading. The defense attorney argued that the charge was defective due to duplicity in the indictment.