DEFENDANT. Arabic mudda’a alaihi مدعي عليه
Lit. “A claim upon him.”
The author of the Hidayah (vol iii p 63) says a defendant is a person who, if he should wish to avoid the litigation, is compellable to sustain it. Some have defined a plaintiff, with respect to any article of property, to be a person who, from his being disseized of the said article, has not right to it but by the establishment of proof; and a defendant to be a person who has a plea of right to that article from his seizing or possession of it.
The Imam Muhammad has said that a defendant is a person who denies. This is correct; but it requires a skill and knowledge of jurisprudence to distinguish the denier in a suit, as the reality and not the appearance is efficient, and it frequently happen that a person is in appearance the plaintiff, whilst in reality he is the defendant. Thus, a trustee when he says to the owner of the deposit, “I have restored to you your deposit,’ appears to be plaintiff, inasmuch as pleads the return of the deposit; yet in reality he is the defendant, since he denies the obligation of responsibility, and hence his assertion, corroborated by an oath, must be credited.
Based on Hughes, Dictionary of Islam