An Affidavit document is a document sworn or affirmed, under Oath, and a document for which the truthfulness of the statements within must be genuinely true. An affidavit is a sworn, or affirmed, legal document.It is a written statement that serves as evidence. Affiant: one who swears to an affidavit; deponent. Affidavit: a sworn or affirmed statement made in writing and signed; if sworn, it is notarized. An affidavit is a sworn statement, notarized, and purports to be the whole truth as you know it. If a written statement of facts is sworn under oath as being the truth, it is called an affidavit. An affidavit is a written statement sworn or affirmed to be true in front of a lawyer, notary public, or commissioner for taking affidavits. It must be signed in the presence of a notary or authorized official to be valid. Why is a sworn affidavit important in legal proceedings?