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.

Adeyemi's lawyer, prominent human rights advocate Femi Falana, told the BBC that Adeniyi had since been released, and that detaining a relative in place of a suspect was illegal in Nigeria.

From BBC • Jul. 11, 2026

"OpenAI's nascent hardware business now rests on the shakiest of foundations, rotten to its core by its illegal reliance on misappropriated trade secrets," the complaint said.

From Barron's • Jul. 10, 2026

A spokesperson for the district attorney’s office confirmed prosecutors are reviewing the LAPD’s criminal investigation for potential illegal eavesdropping charges.

From Los Angeles Times • Jul. 9, 2026

This has made it difficult to capture consumers who were switching from cigarettes to smokefree nicotine products and allowed illegal products to fill the void.

From The Wall Street Journal • Jul. 9, 2026

“Ambuya says witch-hunting is a way to get rid of people nobody likes. She says it’s illegal in Zimbabwe.”

From "A Girl Named Disaster" by Nancy Farmer

Vocabulary lists containing illegal

List 3

Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!

"A Natural Balance" and "In My Dreams"

Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!

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

Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!