1
the illegality of sth/doing sth
illegality 常与 the...of 连用，表示某事具有违法性质。
They questioned the illegality of the police search.
他们质疑这次警方搜查的违法性。
违法；不合法；非法性
先理解核心含义，再看它在真实句子里的用法。
违法；不合法；非法性
the state or quality of being illegal; unlawfulness by violating a legal statute
They questioned the illegality of the police search.
他们质疑这次警方搜查的违法性。
多指违法性质；复数 illegalities 指具体违法行为。
非法性。
the state of being illegal
因合同违反法律而对其效力提出的抗辩。
a defense to the validity of a contract because it was in violation of the law
The illegality of the street vendor's actions was obvious to everyone.
街头小贩行为的非法性对每个人来说都很明显。
The defense lawyer challenged the illegality of the search.
辩护律师对搜查的非法性提出质疑。
Many drivers are unaware of the illegality of using a phone while driving.
许多司机没有意识到开车时使用手机的违法性。
illegality 常与 the...of 连用，表示某事具有违法性质。
They questioned the illegality of the police search.
他们质疑这次警方搜查的违法性。
复数形式 illegalities 常指具体的违法行为或违规事项。
The review found several illegalities in the voting process.
审查发现投票过程中存在若干违法行为。
Not this
The illegal of this action is clear.
Use this
The illegality of this action is clear.
illegal 是形容词，不能作主语；此处需要名词 illegality，表示‘非法性’。
Not this
The report lists several illegality in the company's procedures.
Use this
The report lists several illegalities in the company's procedures.
illegality 表示抽象的‘非法性’时不可数；表示具体的‘非法行为’时可数，与 several 搭配须用复数 illegalities。
Not this
We must prove the illegality for this decision.
Use this
We must prove the illegality of this decision.
表示‘某事物的非法性’时用介词 of，引出非法行为或决定；不能用 for。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
协议的非法性
The court ruled on the illegality of the agreement.
法院对协议的非法性作出了裁决。
被指称的违法行为
The company faces charges over the alleged illegality of its operations.
该公司因其经营活动中被指称的违法行为而面临指控。
承认违法
The firm refused to admit any illegality.
该公司拒绝承认任何违法行为。
否认违法
The officials denied any illegality in the tender process.
官员们否认招标过程中有任何违法行为。
违法的认定
The judge made a finding of illegality and ordered the contract to be void.
法官认定存在违法行为，并宣布合同无效。
Use illegality naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
把 illegal（非法的）加上名词后缀 -ity，记住开头的 ill（病）——违法就像社会的一种‘病’，即不合法。
语域：formal 常见场景：legal documents、court proceedings、academic writing “Illegality” 多用于正式或法律语境，强调某种行为或状态违反法律；日常口语中比较少见，通常用 “something is illegal” 来表达。
指具体违法行为时可数，复数形式为 illegalities；指“不合法”这一抽象性质时不可数。
Dictionary facts from ECDICT, WIKTIONARY.