The term duplicity means deceitfulness or double dealing. The term duplicity originated from French word ‘duplicite’ and Latin word ‘duplicitas.’
Duplicity of pleading is the pleading of two or more matters in one plea. Common law does not allow duplicity of pleading since it produces confusion and leads to multiplication of issues. It is only a fault in form and alleges two or more distinct grounds of defense for one single purpose or object. Duplicity of pleading may be in declaration or in subsequent proceedings. Duplicity in the declaration consists in joining different grounds of action, in one and the same count. The rule forbidding duplicity of pleading extends to pleas perpetual or peremptory, and not to pleas dilatory. It does not embrace replications, rejoinders, or any of the subsequent pleadings. The inconveniences caused by it were remedied by several statutes and rules. Under such provisions, the defendant may plead as many different pleas in bar but it does not authorize him/her to allege more than one, ground of defense in one plea.