na-adjective, noun which may take the genitive case particle 'no', noun
Describes actions, organizations, or items that are against the law. Often used in formal or legal contexts, contrasting with 違法 (which can imply a clearer violation of specific statutes).
非合法な手段で金を稼いではいけない。
You must not earn money by illegal means.
The organization was involved in unlawful activities.