形容詞 illicit:

1. contrary to accepted morality (especially sexual morality) or convention
2. contrary to or forbidden by law
   同義詞：illegitimate, outlaw, outlawed, unlawful

1. Kept or done in secret, often in order to conceal an illicit or improper purpose.
   秘密的，暗中的保密的或秘密進行的，常為隱藏一個非法的或不正當(dāng)?shù)哪康?/div>
2. A drug, especially an illicit or addictive one.
   麻醉劑尤指非法使用或使人上癮的麻醉劑
3. A love affair, especially an illicit one.
   偷情尤指不正當(dāng)?shù)哪信P(guān)系
4. He makes a lot of money by traffic illicit merchandise.
   他做違禁商品買賣賺了許多錢。

il.lic.it

adj.（形容詞）
Not sanctioned by custom or law; unlawful.
非法的，不正當(dāng)?shù)模翰粸閼T例或法律所允許的；不法的

來源：
Latin illicitus
拉丁語 illicitus
in- [not] * see in-
in- [不] *參見 in-
licitus [lawful] * see licit
licitus [合法的] *參見 licit

【引伸】
illic.itly
adv.（副詞）
illic.itness
n.（名詞）