Emily Dickinson Lexicon

COM-PLAIN'ANT, n. [Fr. complaignant.]

1. A prosecutor; one who prosecutes by complaint, or commences a legal process against an offender for the recovery of a right or penalty. He shall forfeit one moiety to the use of the town; and the other moiety to the use of the complainant. – Stat. of Massachusetts.
2. The plaintif in a writ of Audita Querela. – Ibm.