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hĭlărĭtas, ātis, f. [hilaris], cheerfulness, gayety, good-humor, joyousness, merriment, hilarity (class.): hilaritatem illam, qua hanc tristitiam temporum condiebamus, in perpetuum amisi, Cic. Att. 12, 40, 3; cf.: tristitia deductis, hilaritas remissis (superciliis) ostenditur, Quint. 11, 3, 79: hilaritate et lascivia, Cic. Fin. 2, 20, 65: itaque hilaritatis plenum judicium ac laetitiae fuit, id. de Or. 1, 57, 243: hilaritas illa nostra et suavitas, id. Fam. 9, 11, 1: erat in M. Druso adulescente singularis severitas, in C. Laelio multa hilaritas, id. Off. 1, 30, 108: in praecordiis praecipua hilaritatis sedes, Plin. 11, 37, 77, § 198: ut hilaritate enitescant (oculi), Quint. 11, 3, 75: ceterae hilaritates non implent pectus, Sen. Ep. 23, 3: cum diei permittit hilaritas, fineness, pleasantness, Col. 9, 14, 18: arboris, i. e. a fresh or lively appearance, Plin. 17, 16, 26, § 118.