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 move comes after policies were earlier introduced by Meta that complainants say may unfairly prevent rival AI providers from offering their business services through WhatsApp. —Bloomberg, Mercury News, 15 Apr. 2026

At a hearing at Westminster Magistrates’ Court on March 13, deputy chief magistrate Tan Ikram ruled that Partey must not make any direct or indirect contact with the new complainant, consistent with his existing bail conditions. —Colin Millar, New York Times, 13 Apr. 2026

The complainant claimed they were interrogated for over 12 hours, not allowed to make phone calls and received no food. —Tim Dunn, Boston Herald, 11 Apr. 2026

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

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