DEPONENT
testifier, deponent, deposer
(noun) a person who testifies or gives a deposition
Source: WordNet® 3.1
Etymology
Adjective
deponent (not comparable)
(of some Latin, Greek, Sanskrit, Scandinavian or Old Irish verbs) Having passive form (that is, conjugating like the passive voice), but an active meaning. (Such verbs, originally reflexive, are considered to have laid aside their passive meanings.)
Noun
deponent (plural deponents)
(legal) A witness; especially one who gives information under oath, in a deposition concerning facts known to him or her.
(grammar) A deponent verb.
Source: Wiktionary
De*po"nent, n. Etym: [L. deponenes, -entis, laying down. See Depone,
v. t.]
1. (Law)
Definition: One who deposes or testifies under oath; one who gives
evidence; usually, one who testifies in writing.
2. (Gr. & Lat. Gram.)
Definition: A deponent verb.
Syn.
– 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.
De*po"nent, a. Etym: [L. deponens, -entis, laying down (its proper
passive meaning), p. pr. of deponere: cf. F. déponent. See Depone.]
(Gram.)
Definition: Having a passive form with an active meaning, as certain latin
and Greek verbs.
Source: Webster’s Unabridged Dictionary 1913 Edition