For various different questions or answers we may use terms like illegal, against the law, criminal violation, civil violation, non-criminal, etc?

I am primarily interested in our stylistic choices for terms like illegal or against the law. It seems like most high ranked users prefer to use illegal to mean against any law, even if not a criminal violation. Is it illegal to perform an act if that law is unconstitutional? What if it seems like it would violate current understanding of constitutional rights, but no court has made this ruling. Is that illegal?

How do we specifically delineate when an act could result in actual imprisonment or when an act is just against the law but is a civil violation? What if the law says an act is illegal but there is no punishment an individual could face for violating it (for example, it is illegal to leave the USA without a US passport, but the punishment for leaving without a passport has been repealed).

2 Answers 2


We don't; dictionaries do

Using Merriam-Webster (others will give different results):

illegal: not according to or authorized by law

unlawful: not lawful: constituted, authorized, or established by law

Illegal and unlawful are identified as synonyms. Some dictionaries suggest that illegal has the connotation of being criminal but MW is not one of those. Which brings us to:

crime: an illegal act for which someone can be punished by the government especially : a gross violation of law

This shows us the limits of general dictionaries because there are offenses that are punishable by the government but not criminal like most driving offenses. Which leads to:

offenses: an infraction of law especially : MISDEMEANOR

misdemeanor: a crime less serious than a felony


felony: a: a grave crime formerly differing from a misdemeanor under English common law by involving forfeiture in addition to any other punishment b: a grave crime (such as murder or rape) declared to be a felony by the common law or by statute regardless of the punishment actually imposed c: a crime declared a felony by statute because of the punishment imposed d: a crime for which the punishment in federal law may be death or imprisonment for more than one year

Which shows us the other limitation of dictionaries which is regionalism because the word felony is not used outside the United States except as slang for what replaced them: a serious indictable offense (which has the right of a jury trial) as opposed to a summary offense (which doesn't). This is because, outside the USA, common law countries have not been shackled with a Constitutionally guaranteed right to a jury trial for driving through a red light so they have been able to streamline their justice systems to let a magistrate deal with the crap and only reserve juries for the serious stuff.

An act that could result in imprisonment is "a crime punishable by imprisonment" and I don't really know of any shorthand for that.

  • 1
    jw, do you know how MW compares to Black's? I would be somewhat partial to Black's as the source for definitions on this site, at least as the definitions relate to US law.
    – Andrew
    Jun 22, 2020 at 16:43

In the broadest strokes:

refers to any law whose violation can result in imprisonment or other punishment by the state. Another hint that a law is criminal instead of civil is that violations can only be pursued by (or with the consent of) prosecutorial agents of the state.

refers to all other laws, regulations, or disputes, for which the judicial remedies are limited to fines, money judgments, or the assignment of property. There are separate systems and standards for handling civil and criminal matters.

("is X legal?"): All criminal acts are illegal. Some "illegal" acts are matters of civil law. also covers disputes that are governed by principles of that are more concerned with providing just resolution of grievances than of categorizing every element of a complaint as "legal" or "illegal." So law certainly ventures into questions that would be odd to characterize as "legal or illegal?"

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