Deponent

Part of speech: noun (n.)

1. One who deposes or testifies under oath; one who gives evidence; usually, one who testifies in writing.

2. A deponent verb.

Synonyms: Deponent, Affiant. These are legal terms describing a person who makes a written declaration under oath, with a view to establish certain facts. An affiant is one who makes an affidavit, or declaration under oath, in order to establish the truth of what he says. A deponenet is one who makes a deposition, or gives written testimony under oath, to be used in the trial of some case before a court of justice. See under Deposition.

Part of speech: adjective (a.)

Having a passive form with an active meaning, as certain latin and Greek verbs.