Definitions

illegal

[ih-lee-guhl] / ɪˈli gəl /

ADJECTIVE

against the law

Synonyms

STRONGEST

banned criminal illegitimate illicit irregular outlawed prohibited smuggled unauthorized unconstitutional unlawful unlicensed unwarranted wrongful

WEAK

actionable black-market bootleg contraband crooked extralegal felonious forbidden heavy hot interdicted lawless not approved not legal outside the law proscribed prosecutable racket shady sub-rosa taboo under-the-table unofficial unwarrantable verboten violating wildcat

Antonyms

STRONGEST

authorized blessed ethical good justifiable lawful legal legitimate moral permitted right warranted

WEAK

allowed permissible

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Prediction-market platform Kalshi recently unveiled a swath of “market integrity” updates that all relate to one thing: stopping illegal trading by insiders.

From MarketWatch • Jun. 10, 2026

Jordan’s control of the area was overwhelmingly considered an illegal occupation by the international community.

From The Wall Street Journal • Jun. 10, 2026

Police departments are also trying to educate the public before issuing citations or towing an illegal bike, but officials said it’s a challenge.

From Los Angeles Times • Jun. 10, 2026

It is not illegal in the UK to sell or auction off human remains if they are more than 100 years old.

From BBC • Jun. 9, 2026

On January 6, Nebraska became the thirty-sixth state to ratify the Eighteenth Amendment, making it illegal to manufacture, sell, or transport liquor.

From "1919 The Year That Changed America" by Martin W. Sandler

Vocabulary lists containing illegal

List 3

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"A Natural Balance" and "In My Dreams"

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Fear and Loathing in Cleveland: Trump's RNC Acceptance Speech

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