I heard someone claim that the terms "unlawful" and "illegal" have different meanings. More specifically, they claimed that "illegal" acts are anything expressly forbidden in law (e.g. murder), while "unlawful" acts are anything not expressly permitted in law (e.g. wearing a hat).

This seemed unusual to me, and most dictionaries I could defined "unlawful" as basically synonymous with "illegal".

While there doesn't appear to be any real difference between the terms in "normal" speech, is there any difference in "legalese"?

  • This has been asked, and answered, on EnglishSE
    – user35069
    Commented Mar 17, 2021 at 19:42
  • 2
    There is a distinction between "legal" and "lawful" in that there is a sense of "legal" that isn't the opposite of "illegal," and that sense is not synonymous with "lawful." The sense I have in mind is the one in the sentence they discussed the ethical and philosophical aspects of the question rather than the legal aspects. I agree that the proposed definition of "unlawful" is unusual. I would go farther and say that it is nonsense.
    – phoog
    Commented Mar 17, 2021 at 23:30
  • @GeorgeWhite what law expressly permits the sharpening of a pencil with a sheet of sandpaper? Is that unlawful? What do you make of a statute such as 8 USC 1323 that establishes a crime by expressly declaring the prohibited conduct to be "unlawful"?
    – phoog
    Commented Jul 20, 2023 at 9:06
  • @phoog - you are right. I can’t image what I was thinking when I posted that two years ago, I’ll delete it in a few hours. Commented Jul 20, 2023 at 18:05
  • @GeorgeWhite it seems a common distinction to draw. Note the three upvotes your comment received. I was brought back to this by a recently posted duplicate where someone made the same assertion. As usual with questions about meaning, it's much easier to ask the question than to answer it.
    – phoog
    Commented Jul 20, 2023 at 22:30

1 Answer 1


Yes, but the difference is in nuance, not substance

Illegal means “not according to or authorized by law” and lists unlawful as a synonym.

Unlawful means “not lawful” with illegal as a synonym.

So, by definition, they mean the same thing and can be used interchangeably.

Illegal does carry a slight hint of being more egregious than unlawful and would be more often used of criminality than of a parking offense but it’s not wrong to use them interchangeably.

  • A close application of this definition of "illegal" would agree with the definition of "unlawful" postulated in the question. That is, one might read it as including any matter on which the law is silent as "illegal," which is of course not how the word is actually used. In other words, this definition of "illegal" is not very good.
    – phoog
    Commented Mar 19, 2021 at 18:02

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .