complainant

/kəmˈpleɪnənt/

complainant means one who makes complaint, one who complains.

complainant is pronounced /kəmˈpleɪnənt/.

Etymology

From Old French complaignant, present participle of complaindre.

noun

One who makes complaint, one who complains.“1708-1714 Jeremy Collier, Ecclesiastical History of Great Britain Eager complainants […] in the dispute.”
The party that brings a civil lawsuit against another; the plaintiff.
An alleged victim in a criminal investigation or trial.