Lewis & Short

ĭdōnĕus, a, um, adj. [Sanscr. root indh-, idh-, to kindle; prop. bright, conspicuous; cf. Idus], fit for something (esp. for an action), meet, proper, becoming, suitable, apt, capable, convenient, sufficient (of persons and things; class. and very freq. in prose and poetry; syn.: aptus, opportunus); constr. most commonly with ad, qui, the dat., or absol.; less freq. with in aliquid, the abl., or the inf.

        1. (α) With ad: tot quidem non potuisti adducere homines magis ad hanc rem idoneos, etc., Plaut. Poen. 3, 2, 6: non essem ad ullam causam idoneus, judices, si hoc non viderem, Cic. Clu. 6, 17: ad amicitiam esse idoneus, id. Lael. 17, 62: loco pro castris ad aciem instruendam opportuno atque idoneo, Caes. B. G. 2, 8, 3: cum statim auditoris animum nobis idoneum reddimus ad audiendum, Auct. Her. 1, 4, 6: est enim (lex) ratio mensque sapientis, ad jubendum et ad deterrendum idonea, Cic. Leg. 2, 4, 8: scientia opportunitatis idoneorum ad agendum temporum, id. Off. 1, 40, 142: ad captandos lacertos tempestates non sunt idoneae, id. Att. 2, 6, 1: consilia idonea ad hoc nostrum negotium, id. ib. 5, 6, 1 al.
        2. (β) With qui, or a rel. adverb: video hercle ego te me arbitrari, Euclio, hominem idoneum, Quem senecta aetate ludos facias, Plaut. Aul. 2, 2, 74; cf. Ter. And. 3, 2, 12; 4, 4, 18: utrum ille (Pompeius) idoneus non est, qui impetret, etc., Cic. de Imp. Pomp. 19, 57: tibi fortasse idoneus fuit nemo, quem imitarere, id. Verr. 2, 3, 16, § 41: idonea mihi Laelii persona visa est, quae de amicitia dissereret, id. Lael. 1, 4: et rem idoneam, de qua quaeratur, et homines dignos, quibuscum disseratur, putant, id. Ac. 2, 6, 18: nequeo mearum rerum initium ullum invenire idoneum, Unde exordiar narrare, quae, etc., Ter. Hec. 3, 3, 1.
        3. (γ) With dat.: erit alius (discipulus) historiae magis idoneus, Quint. 2, 8, 7; 12, 10, 49: idoneus arti Cuilibet, Hor. Ep. 2, 2, 8: non sat idoneus Pugnae ferebaris, id. C. 2, 19, 26: vixi puellis nuper idoneus, id. ib. 3, 26, 1: cum idoneos rhetori pueros putaverunt, Quint. 2, 3, 1: Falernum mihi semper idoneum visum est deversorio, Cic. Fam. 6, 19, 1: castris idoneum locum deligit, Caes. B. G. 6, 10, 2; 7, 35, 4: ad cibos viribus conservandis idoneos redeunt, Quint. 2, 10, 6: (volunt poëtae) simul et jucunda et idonea dicere vitae, Hor. A. P. 334: metuensque futuri In pace, ut sapiens, aptarit idonea bello, id. S. 2, 2, 111: ut patriae sit idoneus, serviceable, Juv. 14, 71.
          With dat. gerundi (post-Aug.): Julius, qui perferendis militum mandatis habebatur idoneus, Tac. A. 1, 23 fin.
        4. (δ) Absol.: cujus (Cethegi) eloquentiae est auctor, et idoneus quidem mea sententia, Q. Ennius, etc., a proper, sufficient voucher, Cic. Brut. 15, 57: auctor, Quint. 1, 4, 20; 2, 4, 42: qui si adductus gratia minus idoneum hominem praemio affecisset, etc., i. e. deserving, worthy, Cic. Balb. 3, 7; cf. id. Off. 2, 15, 54: idoneus suae rei quisque defensor, Quint. 4, 1, 46: imperator, id. 12, 3, 5: juvenis, id. 10, 5, 21: debitor, safe, able to pay (opp. inops), Dig. 4, 4, 27 fin.; so, tutor, ib. 26, 1, 9; 27, 8, 1: homines, ib. 35, 2, 88; cf. Sen. Ben. 4, 39: servi conscii, tempus idoneum, locus opportune captus ad eam rem, Cic. Rosc. Am. 24, 68: tempora, Quint. 12, 11, 18; cf.: lex promulgata idoneo die, id. 2, 4, 35: minus idoneis (verbis) uti, Cic. de Or. 1, 34, 154; cf.: aptum atque idoneum verbum, Quint. 9, 4, 144: vox actoris, id. 12, 7, 1: lectio, id. ib. 8 praef. § 28: cautio, Dig. 40, 4, 50: paries, safe, sound, ib. 39, 2, 36: navis, ib. 19, 2, 13: pignora, sufficient, satisfactory, ib. 22, 1, 33.
          Comp. (post-class.): si persona idoneior accedat ad emptionem, Dig. 18, 2, 4, § 6; cf. ib. 47, 23, 2; 43, 29, 3; 50, 6, 5 fin.; Tert. adv. Herm. 18; Anim. 18 (al. idonior or idoneor).
          Subst.: in deligendis idoneis judicium et diligentiam adhibere, Cic. Off. 2, 18, 62: cum idoneis collocutus, Liv. 34, 25, 7: nullo idoneo respondente, Suet. Ner. 44; Quint. 7, 4, 39: novum illud exemplum a dignis et idoneis ad indignos et non idoneos transfertur, Sall. C. 51, 27: per idoneos et secreti ejus socios, Tac. A. 2, 39: apud idonea provinciarum, i. e. at proper stations, id. ib. 4, 5.
          (ε) With in and acc.: infirmi et in nullam spem idonei, Sen. Contr. 5, 33: componere materias in hoc idoneas, ut, etc., Quint. 6, 3, 15.
          *(ζ) With abl. (like dignus): res idoneas dignitate suā judicare, Auct. Her. 3, 3, 5.
          (η) With inf. (poet. and postclass.): fons etiam rivo dare nomen idoneus, i. e. large enough, Hor. Ep. 1, 16, 12: si torrere jecur quaeris idoneum, id. C. 4, 1, 12: accendi idonea, Sen. N. Q. 1, 15, 1.
          Comp.: idoneor (late Lat.), Dig. 18, 2, 4, § 6; 47, 23, 2; Tert. adv. Herm. 18; id. de Anim. 18.
          Hence, adv.: ĭdōnĕē, fitly, suitably, properly, duly, sufficiently (very rare): exordium est oratio animum auditoris idonee comparans ad reliquam dictionem, Cic. Inv. 1, 15, 20: ergo cavendum est idonee. Quid est idonee? Satisdato utique aut pignoribus datis, enough, Dig. 40, 5, 4: cavere, ib. 5, 3, 41; 27, 8, 1: magis idonee reficere parietem, more safely, solidly, ib. 39, 2, 41.
          Comp.: idonius, Tert. Pall. 3 med.