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

The complaints published on BrokerCheck do not include any other details, and the complainants are not identified. — Charlotte Observer, 2 Sep. 2026

The Crown Prosecution Service declined the offer to safeguard the complainants, the filing says. — Tim Stelloh, NBC news, 27 Aug. 2026

Richard Luker, who served as the school’s head of science in the late 1980s, testified that the first complainant’s mother raised concerns that her son was planning to travel abroad with Bowen at the end of the school term. — Christina Coulter, PEOPLE, 27 Aug. 2026

Blackbox soon established that the complainant did not wish to participate, and alleges that 5 was aware of the individual’s reluctance to be the subject of a series based on their experience. — Jake Kanter, Deadline, 25 Aug. 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