Autrefois Acquit Definition:

French word now part of English criminal law terminology.

Refers to an accused who cannot be tried for a crime because the record shows he has already been subjected to trial for the same conduct and was acquitted.

If the accused maintains that the previous trial resulted in conviction, he or she pleads "autrefois convict."

Autrefois attaint is another similar term; "attainted" for a felony, a person cannot be tried again for the same offence.

Any attempt to re-try a person for the same offence can be met with the defence of double jeopardy.