term:

Void-For-Vagueness Doctrine

void-for-vagueness doctrine n

: a doctrine requiring that a penal statute define a criminal offense with sufficient definiteness that ordinary people can understand what conduct is prohibited and in a manner that does not encourage arbitrary and discriminatory enforcement NOTE: Under the void-for-vagueness doctrine, a vague law is a violation of due process because the law does not provide fair warning of a prohibition and fails to set standards for enforcement that would govern the exercise of the police power.

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.