complainant

noun

com·​plain·​ant kəm-ˈplā-nənt 

1

: the party who makes the complaint in a legal action or proceeding

2

: one who complains

Synonyms of complainant

• plaintiff

Examples of complainant in a Sentence

the complainant charged that the defendant had broken the ironclad contract that both had signed

Recent Examples on the Web

That means independent investigation capacity, timely communication with complainants and genuine protection against retaliation. — Jonathan H. Westover, Forbes.com, 30 Oct. 2026

London’s Southwark Crown Court has heard from the complainants, one of whom says she was raped by Brand in a Bournemouth hotel room after the Labour Party conference in 1999. — Lily Ford, HollywoodReporter, 30 Oct. 2026

Four of the six complainants worked in the television and radio industry at the time of their encounter with Brand. — Jake Kanter, Deadline, 30 Oct. 2026

Another complainant, Rosana Vaccon, said she was isolated from her family and never received letters from her mother informing her of her father’s serious illness. — ABC News, 29 Oct. 2026

Word History

First Known Use

15th century, in the meaning defined at sense 1

Kids Definition

complainant

noun

com·​plain·​ant kəm-ˈplā-nənt 

1

: one who makes a legal complaint

2

: one who complains

Legal Definition

complainant

noun

com·​plain·​ant kəm-ˈplā-nənt 

: the party (as a plaintiff or petitioner) who makes the complaint in a legal action or proceeding