complainant

Etymology

From Old French complaignant, present participle of complaindre.

noun

1. (law) The party that brings a civil lawsuit against another; the plaintiff.
2. (law) An alleged victim in a criminal investigation or trial.
3. One who makes complaint.
   1708-1714 Jeremy Collier, Ecclesiastical History of Great Britain Eager complainants […] in the dispute.
   The Southern Region takes, in the main, a candid line with its public. … An ill-informed attempt to blackguard the railway publicly is likely to see the complainant put politely—but very firmly—in his place. 1962 August, “Let's have plain speaking”, in Modern Railways, page 73