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 complainant told police the check was in an envelope handed to a clerk at the Bridgeview post office. —Dennis Sullivan, Chicago Tribune, 25 Mar. 2026

But complainants can file an appeal with the California Department of Education, depending on the district’s determination. —Molly Gibbs, Mercury News, 25 Mar. 2026

While his name is redacted in the interview, an email sent days later identifies the complainant as officer Michael Kearins, and a subpoena for Kearins by OIG agents is included in the files. —Julie K. Brown, Miami Herald, 21 Mar. 2026

Two of the claimants were complainants who gave evidence ​during Spacey's 2023 criminal trial in London, where ​the now 66-year-old actor was acquitted of all charges. —Reuters, NBC news, 19 Mar. 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