A more thorough explanation:

Definition: Non est factum is a Latin term that means "it is not his deed." It is a legal defense used to deny the execution of a document that is being sued on.

Examples:

• General non est factum: This is a broad denial that an instrument was executed or executed properly. For example, a defendant may use this defense to deny that they signed a contract.
• Particular non est factum: This is a more specific denial that an instrument's execution is invalid or nonbinding. For example, a defendant may use this defense to argue that they were forced to sign a contract under duress.
• Verified non est factum: This is a sworn denial that not only questions the validity of the signature but also the validity of the entire document. For example, a defendant may use this defense to argue that they never signed a document and that the signature is a forgery.

These examples illustrate how non est factum can be used as a defense in different situations. It is a way for a defendant to deny that they executed a document and to challenge its validity.