un‧con‧sti‧tu‧tion‧al AC /ˌʌnkɒnstəˈtjuːʃənəl, ˌʌnkɒnstɪˈtjuːʃənəl $ -kɑːnstəˈtuː-/ adjective
not allowed by the constitution (=set of rules or principles by which a country or organization is governed):
claims that the President’s action was unconstitutional
—unconstitutionally adverb

[TahlilGaran] Dictionary of Contemporary English ▲

illegal forbidden by law:
It is illegal to sell tobacco to children under 16.
illegal immigrants
He was carrying an illegal weapon.
be against the law to be illegal. This phrase is very commonly used in everyday English, instead of saying that something is illegal:
Driving a car without insurance is against the law.
It’s against the law to hit a child.
unlawful illegal - a rather formal word, which is used especially when this particular action is considered to be illegal, although there are some situations where such actions can be legal:
The judges said that the strike was unlawful.
The money was obtained by unlawful means.
a verdict of unlawful killing
illicit illicit activities or goods are illegal and usually kept secret:
Marijuana remains the most commonly used illicit drug in the United States.
the illicit trade in stolen cattle
illegitimate not allowed or acceptable according to rules or agreements:
the illegitimate use of power
The election results were declared to be illegitimate.
illegitimate share trading
unconstitutional not allowed by a country’s constitution (=set of rules and principles by which a country is governed):
The court ruled that the new law was unconstitutional.

[TahlilGaran] English Thesaurus ▲