noun
nulla poena sine lege; principle of legality in criminal law
A fundamental legal principle that no act can be punished unless it was defined as a crime by law at the time it was committed. Used in legal and academic contexts.
罪刑法定主義は近代刑法の大原則である。
The principle of legality is a fundamental principle of modern criminal law.
罪
Under the principle of legality, there is no crime without a law.