English Reference
adjective · noun

illicit

adj. · n.
US /ˌɪˈɫɪsət/ UK /ɪlˈɪsɪt/ il·lic·it

  1. 01 C1 Advanced Formal Law

    adj.not allowed by law.

    adj.forbidden by law, rules, or custom; often used to describe trade or activities that are hidden from authorities.

    Simple

    The police are trying to stop the illicit trade of stolen goods.

    In context

    The investigation uncovered a vast network involved in the illicit trafficking of protected wildlife across international borders.

    Usage

    Commonly collocates with nouns like 'trade', 'drugs', 'activities', or 'gains'.

  2. 02 C2 Proficiency FormalLiterary

    adj.not allowed by social rules or morals, even if not strictly against the law.

    adj.contrary to accepted social or ethical standards; often used in the context of secret relationships.

    Simple

    They had an illicit romance that they kept secret from their families.

    In context

    The novel explores the tragic consequences of their illicit affair within the rigid social structure of the nineteenth century.

  3. 03 C2 Proficiency TechnicalFormal Law

    n.things that are illegal to own or sell.

    n.substances or goods that are prohibited by law.

    Simple

    Customs officers searched the ship for any illicits hidden in the cargo.

    In context

    The new legislation aims to tighten controls on the sale of chemical precursors used to manufacture various illicits.

    contrabandprohibited goods
Don't confuse

illicit vs elicit — Elicit is a verb meaning to draw out a response; illicit is an adjective meaning illegal or forbidden.

Usage illicit drugs

He was prescribed pregabalin to treat his anxiety, but his mother says he "became addicted" and started boosting his supply by buying the drug from illicit websites.

BBC News· 18 Aug 2026

This is compounded when illicit commercial industries, known as the “education mafia”, exploit student desperation by stealing and then selling exam papers, something that has become widespread in India and elsewhere.

The Guardian· 16 Aug 2026

Borrowed from French illicite, from Latin illicitus, from in- (“not”) + licitus (“allowed, permitted”), from licet (“it is allowed”). By surface analysis, il- + licit.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Latin illicitus
Level C1 · Advanced
Frequency Frequent
Updated