per-fămĭlĭāris

e, adj.
I. very intimate, very familiar (class.): perfamiliaris Philisto, Cic. Q. Fr. 2, 11 (13), 4.—In tmesi: Phaedon Socrati per fuit familiaris, Gell. 2, 18, 1.—
II. Subst.: perfămĭlĭāris, is, m., a very intimate or familiar friend (class.): meus, Cic. Fam. 13, 51: Epicuri, id. Fin. 5, 31, 94: M. Antonii, id. Brut. 45, 168.
Lewis & Short
A Latin Dictionary, 1879
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