ETYM French complaignant, p. pr. of complaindre.
1. One who makes complaint.
2. One who commences a legal process by a complaint.
3. The party suing in equity, answering to the plaintiff at common law.

One who complains or laments; one who finds fault.

A person who makes demands.

One who brings a charge of libel

One praying humbly for something:; SYN. suppliant, supplicant.

ETYM French plaintif making complaint, plaintive; in Old French equiv. to plaignant complainant, prosecutor, from plaindre. Related to Plaint, Plaintive.
A person who brings an action in a court of law; SYN. complainant.
In law, a person who brings a civil action in a court of law seeking relief (for example, damages).