Lewis & Short

ăpocrĭsĭārĭus or ăpocrĭsārĭus, ii, m. [ἀποκρινομαι, to answer; ἀπόκρισις, an answer] (late Lat.), a delegate, deputy, who performs a duty in the place of another, esp. of a high Church officer, called also responsalis, Julian. Epit. 6, 26; cf. Just. Nov. 6, 2; Hon. Aug. G. Anim. 1, 185.