Lewis & Short

† hĭlăris, e, and hĭlărus, a, um, adj., = ἱλαρός [cf. Sanscr. hlād, rejoice; Gr. χλαρός; Engl. glad],

  1. I. cheerful, of good cheer, lively, gay, blithe, merry, jocund, jovial.
    Adj.     (class.; syn. laetus).
          1. (α) Form hilaris: oderunt hilarem tristes tristemque jocosi, Hor. Ep. 1, 18, 89; cf.: hoc (vultu) tristes, hoc hilares sumus, Quint. 11, 3, 72: si tristia dicamus hilares, id. ib. 67: esse vultu hilari atque laeto, Cic. Tusc. 1, 42, 100: hilari animo esse, id. Q. Fr. 2, 13, 1; cf.: aliquem hilari ingenio et lepide accipere, Plaut. Most. 1, 4, 6: ut hunc festum diem Habeamus hilarem, id. Poen. 5, 6, 30: hilarem hunc sumamus diem, Ter. Eun. 4, 5, 5: laetum hilaremque diem sentire, Juv. 15, 41: hilaris fluit (vox), Quint. 11, 3, 63: oratio (opp. tristis), id. 8, 3, 49: causae (opp. tristes), id. 11, 3, 151: adulescentia, id. 8, 6, 27: id quod dicitur aut est lascivum et hilare aut contumeliosum. … In convictibus lasciva humilibus hilaria omnibus convenient, id. 6, 3, 27: infernis hilares sine regibus umbrae, Juv. 13, 52.
          2. (β) Form hilarus: tristis sit (servus frugi), si eri sint tristes: hilarus sit, si gaudeant, Plaut. Am. 3, 3, 6; cf.: credam istuc, si esse te hilarum videro, id. As. 5, 1, 10: unde ego omnes hilaros, lubentes, laetificantes faciam ut fiant, id. Pers. 5, 1, 8: fac te hilarum, cheer up, Ter. Ad. 4, 7, 38; 5, 3, 56: hunc (librum) lege arcano convivis tuis, sed, si me amas hilaris et bene acceptis, Cic. Att. 16, 3, 1: hilara vita, id. Fin. 5, 30, 92: hilaro vultu, id. Clu. 26, 72; Plin. 7, 19, 18, § 79: fronte hilaro, corde tristi, Caecil. ap. Gell. 15, 9, 1: hilara sane Saturnalia, Cic. Att. 5, 20, 5; Lucr. 2, 1121.
        1. b. Comp.: fac nos hilaros hilariores opera atque adventu tuo, Plaut. Stich. 5, 4, 56: tu quidem pol et multo hilarior, Ter. Eun. 4, 5, 5: hilarioribus oculis quam solitus eras, intuens, Cic. Pis. 5, 11: attulit a te litteras hilariores, id. Att. 7, 25: hilarior protinus renidet oratio, Quint. 12, 10, 28: cutem in facie corrigit coloremque hilariorem facit, brighter, fresher, Plin. 23, 8, 75, § 144; cf. id. 36, 7, 11, § 55; 16, 10, 19, § 48.
        2. c. Sup.: homo lepidissime atque hilarissime! Plaut. Men. 1, 2, 40: conviva, id. Mil. 3, 1, 72.
  2. II. Subst.: hĭlărĭa, ōrum, n., the joyous festival celebrated in honor of Cybele at the vernal equinox, Macr. S. 1, 21: hilaribus, Vop. Aurel. 1: hilariis, Lampr. Alex. Sev. 37.
    Adv.: hĭlăre (class.), and hĭlărĭ-ter (late Lat.), cheerfully, gayly, joyfully, merrily: dicimus aliquem hilare vivere, etc., Cic. Fin. 5, 30, 92; cf.: res tristes remisse, severas hilare tractare, id. de Or. 3, 8, 30; so, hilare, id. ib. 2, 71, 290; Afran. ap. Non. 514, 2; Tac. A. 11, 3; Suet. Ner. 34; Gell. 18, 2, 1: deinde modo acriter, tum clementer, maeste, hilare in omnes partes commutabimus, Auct. Her. 3, 14, 24; 4, 55, 68: hilariter, Aug. Civ. Dei, 5, 26; Vulg. Sap. 6, 17; cf. Neue, Formenl. 2, 660.
    Comp.: si hilarius locuti sunt (opp. in luctu esse), Cic. Tusc. 3, 27, 64; Suet. Calig. 18.