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 business’s behaviors, as described by the numerous complainants, violate the Michigan Consumer Protection Act (MCPA), according to Nessel. —Bailey Richards, PEOPLE, 7 Apr. 2026

The statement said that per the state Government Data Practices Act, the existence and status of the complaints are public, but complainants’ names, the nature of the complaints and other related information are not. —Nick Ferraro, Twin Cities, 4 Apr. 2026

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

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