A more thorough explanation:

A double plea is a legal term that refers to a plea consisting of two or more distinct grounds of complaint or defense for the same issue. For example, a defendant may plead both not guilty and insanity as defenses in a criminal case.

Another example of a double plea is a conditional plea, which is a plea of guilty or nolo contendere entered with the court's approval and the government's consent, while reserving the right to appeal any adverse determinations on one or more pretrial motions.

Double plea is different from alternative pleading, which is a pleading that sets forth two or more statements of a claim or defense alternatively or hypothetically, such as pleading breach of contract and unjust enrichment in the alternative.

Overall, a double plea allows a defendant to assert multiple defenses or complaints in a single plea, which can be useful in certain legal situations.