A more thorough explanation:

Autrefois (oh-truh-fwah) is a Law French term that means "on another occasion" or "formerly." It is often used in legal contexts to refer to a previous legal action or decision that has a bearing on a current case.

• Autrefois acquit is a plea in bar of arraignment that the defendant has been acquitted of the offense. For example, if someone is charged with a crime and found not guilty, they cannot be tried again for the same crime based on new evidence that comes to light later.
• Autrefois convict is a plea in bar of arraignment that the defendant has been convicted of the offense. This means that if someone is convicted of a crime, even if they are let off lightly, they cannot be charged again for the same crime based on new evidence.
• Autrefois attaint is a plea in bar that the defendant has already been attainted for one felony and therefore cannot be prosecuted for another.

These examples illustrate how the term autrefois is used in legal contexts to refer to previous legal actions or decisions that have a bearing on a current case. It is important to understand these concepts in order to ensure that defendants are not subjected to double jeopardy or other unfair legal practices.