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

• 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 complainants argued that in fact, IEEPA doesn’t give the president power to impose taxes or tariffs at all, and it hasn’t been used to do so during any of the 69 times it’s been invoked since it was established in 1977. —Kate Nishimura, Sourcing Journal, 21 Oct. 2025

Court filings from a 2023 $75 million class-action settlement with Epstein’s victims reveal how Deutsche Bank became what the complainants alleged was the financial backbone of Epstein’s criminal enterprise from 2013 to 2018. —Lily Mae Lazarus, Fortune, 8 Oct. 2025

If the noise continues, the department requires the complainant to document the dates and times of the disturbance in a second letter. —Gina Lee Castro, jsonline.com, 8 Oct. 2025

When complainants respond to outreach and indicate a desire to pursue a complaint, the university takes action. —Kansas City Star, 24 Sep. 2025

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