Lewis & Short

1. pĕnĭtus, a, um, adj. [root pa- of pasco; v. penates], inward, inner, interior (ante- and post-class.): exscrea usque ex penitis faucibus, Plaut. As. 1, 1, 28: scaturigo fontis, App. M. 6, p. 178, 33: mente penitā conditum, id. ib. 11, p. 259, 38.
Comp. penitior pars domūs, App. Fragm. ap. Prisc. p. 599 P.
Sup.: advecta ex Arabiā penitissimā, Plaut. Pers. 4, 3, 53; so id. ib. 4, 3, 71: in latebras abscondas pectore penitissimo, id. Cist. 1, 1, 65: Scythae illi penitissimi, the most remote, Gell. 9, 4, 6: de Graecorum penitissimis litteris, Macr. S. 5, 19.
As subst.: pĕnĭta, ōrum, n., the inmost parts: mundi, Mart. Cap. 1, § 9: terrae, id. 6, § 600: sacri loci, Jul. Val. Rer. Gest. Alex. 3, 43.
Hence, adv., in two forms.

  1. A. pĕnĭtē (poet. and post-class.), inwardly, internally, Cat. 61, 178.
    Sup.: penitissime, Sid. Ep. 4, 9.
  2. B. pĕnĭtus (class.), inwardly, internally, in the inside (cf.: prorsus, omnino).
    1. 1. Lit.
      1. a. In gen. (only poet.): extra penitusque coacti Exagitant venti, Sev. Aetn. 317: penitusque deus, non fronte notandus, Manil. 4, 309.
      2. b. In partic., deeply, far within, into the inmost part (class.): saxum penitus excisum, Cic. Verr. 2, 5, 27, § 68: argentum penitus abditum, id. Off. 2, 2, 13: jacent penitus defossa talenta, Verg. A. 10, 526: penitus convalle virenti, id. ib. 6, 679: penitus terrae defigitur arbos, id. G. 2, 290: penitus penetrare, Cels. 5, 26, 7: Suevos penitus ad extremos fines se recepisse, Caes. B. G. 6, 9: penitus in Thraciam se abdidit, Nep. Alcib. 9: mare retibus penitus scrutare, Juv. 5, 95.
        1. (β) Trop., deeply, far within. from the innermost depths or recesses: penitus ex intimā philosophiā hauriendam juris disciplinam putas, from the very depths of philosophy, Cic. Leg. 1, 5, 17: opinio tam penitus insita, so deeply rooted, id. Clu. 1, 4: bene penitus sese dare in familiaritatem alicujus, id. Verr. 2, 2, 70, § 169: periculum penitus in venis et visceribus rei publicae, in the very heart, id. Cat. 1, 13, 31: demittere se penitus in causam, id. Att. 7, 12, 3.
    2. 2. Transf. (qs. through and through, to the bottom of a thing, i. e.), thoroughly, completely, wholly, entirely, utterly (class.): caput et supercilia penitus abrasa, Cic. Rosc. Com. 7, 20: utrum hic confirmasse videtur religionem an penitus totam sustulisse? id. N. D. 1, 42, 119: res penitus perspectae, id. de Or. 1, 23, 108: penitus pernoscere omnes animorum motus, id. ib. 1, 5, 17: quod in memoriā meā penitus insederit, id. ib. 2, 28, 122: intellegere aliquid, id. Att. 8, 12, 1: amittere hanc consuetudinem et disciplinam, id. Off. 2, 8, 27: diffidere rei publicae, id. Fam. 5, 13, 5: perdere se ipsos, id. Fin. 1, 15, 49: te penitus rogo ne, etc., Q. Cic. ap. Cic. Fam. 16, 8, 1: penitus toto divisos orbe Britannos, Verg. E. 1, 66: dilecta penitus, Hor. C. 1, 21, 4.
      Hence, to strengthen the comp.: penitus crudelior, far more, Prop. 1, 16, 17.
      To strengthen the sup.: vir penitus Romano nomini infestissimus, Vell. 2, 27, 1.