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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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 Federal law is supposed to protect consumers from unauthorized electronic transfers, and regulators have said that a transfer set in motion by a fraudster counts as unauthorized even when the victim was tricked into handing over account credentials. — Pawan Jain, The Conversation, 14 Sep. 2026 Ellifson said the cameras have led to a faster police response to potential critical emergencies and have been used to quickly notify law enforcement about unauthorized individuals entering school property. — Alec Johnson, jsonline.com, 11 Sep. 2026 In Anthropic’s new cybersecurity report, the AI lab detailed an episode in which its Mythos 5 model was undergoing testing and gained unauthorized access to the internet. — J.d. Capelouto, semafor.com, 11 Sep. 2026 However, alcohol consumption is generally not permitted on public streets, sidewalks and other unauthorized public spaces. — Gabby Sartori, USA Today, 10 Sep. 2026 See All Example Sentences for unauthorized

Recent Examples of Synonyms for unauthorized

Adjective

Otherwise, every losing party would have an incentive to scour deliberations for something improper.

— Monu Bedi, Chicago Tribune, 20 Sep. 2026
Six additional citations — speeding, improper passing, failing to drive in a single lane, following too closely, failing to obey traffic control and running a red light — have been added to his charges.

— Jordan McPherson, Miami Herald, 19 Sep. 2026

Definition of improper

Adjective

China has strengthened its seed protection laws several times in the last few years; similarly, Japan passed new legislation in July to prevent the illicit export of homegrown varieties.

— Jessie Yeung, CNN Money, 19 Sep. 2026
According to the manufacturer, the system is designed to deactivate organic medications including opioids, most illicit drugs and vape fluid in different forms like pills, liquid and patches.

— Sunny Linnebur, The Conversation, 18 Sep. 2026

Definition of illicit

Adjective

But after his son Eugene Horsch, 44, was arrested in June on charges involving unlawful firearms and forgery, police made a series of unsettling discoveries at the family home on Chew Avenue in Philly's Olney neighborhood.

— Michael Ruiz, FOXNews.com, 19 Sep. 2026
Plummer has a history of violent charges in Cook County, including domestic battery and unlawful use of a weapon by a felon, authorities said.

— Allison Kiehl, Chicago Tribune, 18 Sep. 2026

Definition of unlawful

Adjective

Laying an egg against the Raiders in Year 3 of the Harbaugh era is unacceptable.

— Alejandro Avila OutKick, FOXNews.com, 21 Sep. 2026
Kip Dellinger Santa Monica The type of play by the Chargers on Sunday was completely unacceptable, lackluster and disappointing for a team with Super Bowl aspirations.

— Los Angeles Times, Los Angeles Times, 19 Sep. 2026

Definition of unacceptable

Adjective

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
Internet discussions portrayed the SPLC as a politically motivated or illegitimate actor.

— Art Jipson, The Conversation, 20 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 24 Sep. 2026.

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Synonyms of unauthorized

adjective

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