How to say "illicit" in Japanese

• 違法いほうCommon
  na-adjective, no-adjectiveCovers the core sense of 'illicit': conduct forbidden by law — the direct equivalent of 'illegal' or 'unlawful'. Use it for outlawed acts, dealings, or possessions in ordinary and legal contexts alike.
  あそこに駐車ちゅうしゃするのは違法いほうです。↗

  It is illegal to park a car there.
• 裏口うらぐちJLPT N2approx.Common
  no-adjectiveLiterally a 'back door' or rear entrance; as 'illicit' it is figurative — the 'backdoor' sense of entering or obtaining something through unauthorized channels. It is narrow: not the word for law-breaking in general.
  彼かれは裏口うらぐち入学にゅうがくした。↗

  He bought his way into college.

違法 matches the plain sense of 'illicit' — forbidden by law; 裏口, literally 'back door', fits only the figurative 'backdoor' sense of unofficial, unauthorized access, and is otherwise a marginal rendering.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 違法いほうillegal
• 背徳的はいとくてきimmoral
• 黒いくろいsuspicious
• 裏口うらぐちunauthorized