Meaning of “illegal” in the English Dictionary

"illegal" in British English

See all translations

illegaladjective

uk /ɪˈliː.ɡəl/ us /ɪˈliː.ɡəl/

B2 not allowed by law:

a campaign to stop the illegal sale of cigarettes to children under 16
Prostitution is illegal in some countries.
It is illegal to drive a car that is not registered and insured.
Cocaine, LSD, and heroin are all illegal drugs/substances.

More examples

illegally
adverb uk /ɪˈliː.ɡəl.i/ us /ɪˈliː.ɡəl.i/

B2

They entered the country illegally.
an illegally parked car

illegalnoun [ C ]

informal

(Definition of “illegal” from the Cambridge Advanced Learner’s Dictionary & Thesaurus © Cambridge University Press)

"illegal" in American English

See all translations

illegaladjective

us /ɪˈli·ɡəl/

against the law:

Fireworks are illegal in many places.
illegal immigrant/alien

An illegal immigrant/alien is a person who has entered a country without government permission.

illegally
adverb us /ɪˈli·ɡə·li/

(Definition of “illegal” from the Cambridge Academic Content Dictionary © Cambridge University Press)

"illegal" in Business English

See all translations

illegaladjective

uk /ɪˈliːɡəl/ us

LAW not allowed by law:

According to state law, smoking is illegal in all public buildings.
illegal (for sb) to do sth It is illegal for a company to force an employee into early retirement.
make sth illegal The new law will make it illegal to record phone conversations without consent.
Compare

IT used to describe a character (= letter, number, or symbol) that you cannot use in a particular place on a computer, because it may create problems:

The colon is the only illegal character for file and folder names.
illegally
adverb

Approximately 500,000 workers enter the country illegally each year.

(Definition of “illegal” from the Cambridge Business English Dictionary © Cambridge University Press)