UNAUTHORIZED Synonyms: 91 Similar and Opposite Words

unauthorized

adjective

Definition of unauthorized

as in improper

without permission; not authorized an unauthorized use of government vehicles Unauthorized personnel are not allowed in the building.

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Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

Recent Examples of unauthorized His misdemeanor charges include following too closely and affixing an unauthorized sun screening device to a motor vehicle, jail records show. — Tanya Babbar, Houston Chronicle, 29 Sep. 2026 Platforms that comply with the notice-and-takedown process would receive liability protection, while those that knowingly fail to remove unauthorized replicas could face penalties of up to $750,000. — Shira Lazar, Washington Post, 29 Sep. 2026 After a weekend of alarming headlines about AI mishaps, public sector breaches, and agents gaining unauthorized access to outside systems, tech and AI CEOs are descending on Washington yet again this week. — Ashley Gold, semafor.com, 28 Sep. 2026 Prosecutors allege Del Vecchio commissioned unauthorized background checks against Serfaty as well as other Del Vecchio family members amid an ongoing inheritance dispute. — Gary Baum, HollywoodReporter, 28 Sep. 2026 See All Example Sentences for unauthorized

Recent Examples of Synonyms for unauthorized

Adjective

Electrical issues — like faulty wiring, overloaded power strips, and improper extension cord usage — are the leading cause of fatal fires so far this year.

— Lillian Bonsignore, New York Daily News, 4 Oct. 2026
The action comes as Livingston locals raised concerns about the film’s impact on local business — and notably the city’s sole food bank — as well as improper notification about hazardous stunts.

— Payton Turkeltaub, Variety, 4 Oct. 2026

Definition of improper

Adjective

The Financial Action Task Force, the global money-laundering watchdog, has warned that criminals exploit citizenship and residency programs to conceal their identities, launder illicit wealth and evade justice.

— Arkansas Online, Arkansas Online, 3 Oct. 2026
Those illicit techniques include attaching a GPS tracker to a car or using cell-tower data to track a potential offender.

— Rafael A. Mangual, Washington Post, 2 Oct. 2026

Definition of illicit

Adjective

In a blow to the investment migration industry, the European Union's top court ruled Malta's golden passport program unlawful in April 2025, declaring that EU citizenship could not be sold.

— Arkansas Online, Arkansas Online, 3 Oct. 2026
In a blow to the investment migration industry, the European Union’s top court ruled Malta’s golden passport program unlawful in April 2025, declaring that EU citizenship could not be sold.

— Isabel Debre, Los Angeles Times, 2 Oct. 2026

Definition of unlawful

Adjective

The Portland Trail Blazers fired new play-by-play television broadcaster Braiden Bell on Thursday when past inappropriate social media posts resurfaced just hours after the team announced his hiring.

— ABC News, ABC News, 2 Oct. 2026
Sheriff’s officials said, investigators as of Thursday had not uncovered evidence indicating Chen had inappropriate physical contact with a child.

— Rosalio Ahumada, Sacbee.com, 2 Oct. 2026

Definition of inappropriate

Adjective

With a team that has a margin of error as small as the Dolphins, these penalties are unacceptable.

— Miami Herald, Miami Herald, 5 Oct. 2026
Likewise, the underlying crisis of commercially unacceptable risk in the Strait isn’t anywhere close to being resolved.

— David Faris, Washington Post, 5 Oct. 2026

Definition of unacceptable

Adjective

None of that is illegitimate, and none of it shows up on a data-residency dashboard.

— Dr. Aditya Vikram Kashyap, Forbes.com, 22 Sep. 2026
The researchers suspect that others were created by AI that either hallucinated or, just like the AI agents browsing their file, couldn’t distinguish between legitimate and illegitimate instructions.

— Dan Goodin, ArsTechnica, 27 Aug. 2026

Definition of illegitimate

Browse Nearby Words

unauthentic

unauthorized

unavailability

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Style

“Unauthorized.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/unauthorized. Accessed 8 Oct. 2026.

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Synonyms of unauthorized

adjective

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