countersue

verb

coun·​ter·​sue ˈkau̇n-tər-ˌsü 

variants or less commonly counter-sue

countersued also counter-sued also countersuing also counter-suing

transitive + intransitive

: to sue (someone) in return : to bring a counterclaim against someone

They were dissuaded from suing one another because they knew their target likely had patents that covered similar territory and they could be countersued quickly—the legal equivalent of mutually assured destruction.

—Steven Levy

Appellant countersued, alleging that respondent's interest charges were usurious and that he had breached his fiduciary duty to her.

—Peterson v. Gustafson, 584 N.W. 2d 660 (1998)

Examples of countersue in a Sentence

Recent Examples on the Web

Rodriguez also is asking the court to block Coeytaux from countersuing under California’s shield law, which allows individuals to recover damages and attorneys fees from anyone who files a civil action against them for providing reproductive care that’s legal in California. —Hannah Fry, Los Angeles Times, 3 Feb. 2026

Mathis already has countersued in two other cases. —Patrick Danner, San Antonio Express-News, 3 Feb. 2026

In 2024, Yale New Haven Health and Prospect Medical sued and countersued each other over the true value of the hospitals. —Katy Golvala, Hartford Courant, 31 Jan. 2026

After being notified of the action, Musk’s company almost immediately countersued the conservative influencer, accusing her of violating the platform’s terms of service, which state any disputes with X must be brought in Texas. —Beatrice Nolan, Fortune, 28 Jan. 2026

Word History

First Known Use

1897, in the meaning defined above

Rhymes for countersue

• accrue
• ado
• ainu
• aircrew
• airscrew
• anew
• askew
• baboo
• babu
• bamboo
• beaucoup
• bijou