Lewis & Short

in-firmus, a, um (post-class. infir-mis, e, Amm. 20, 6), adj., not strong, weak, feeble.

  1. I. Lit.: viribus infirmis, Cic. Verr. 2, 4, 43, § 95: valetudo, id. Brut. 48, 180: classis inops et infirma, id. Verr. 2, 5, 33, § 86: valetudo infirmissima, id. de Or. 1, 45.
    Hence, infirm, indisposed, sick: sum admodum infirmus, Cic. Ac. 1, 4, 14; Plin. Ep. 7, 26: pecus, i. e. sheep, Ov. Ib. 44: lumen solis, weak, feeble, Luc. 5, 545: infirmior est panis ex polline, less nourishing, Cels. 2, 18: infirmissimus cibarius panis, id. ib.: saporis vinum, Col. 3, 7: infirmissimae arbores, Plin. 17, 24, 37, § 217: nervi, weak, id. 23, 2, 28, § 59: civitas exigua et infirma, Caes. B. G. 7, 17.
    With ad: infirmi ad resistendum, Caes. B. C. 3, 9, 3: infirmior ad haec omnia, Plin. 36, 20, 37, § 145.
    With adversus: fama, infirmissimum adversus viros fortes telum, Curt. 4, 14.
    In neutr. pl. subst.: infirma, ōrum, the weak parts: lineae, Plin. 9, 43, 67, § 145.
  2. II. Trop., weak in mind or character, superstitious, pusillanimous, inconstant, light-minded: tenuis atque infirmi haec animi videri, Caes. B. C. 1, 32: quippe minuti Semper et infirmi est animi voluptas ultio, Juv. 13, 190: sum paulo infirmior, Hor. S. 1, 9, 71: quorum concursu terrentur infirmiores, Caes. B. C. 1, 3, 5: homines infirmissimi, very uncertain, not to be depended on, Col. 3, 10, 6.
    Of things, of no weight or consequence, weak, trivial, inconclusive: omnino ad probandum utraque res infirma et nugatoria est, Cic. Caecin. 23, 64: quod apud omnes leve et infirmum est, id. Rosc. Com. 2, 6: cautiones, id. Fam. 7, 18: infirmiore vinculo (amicitiae) contrahi, Liv. 7, 30, 2.
    Hence, advv.
    1. A. Form infirmē.
      1. 1. Weakly, faintly, not strongly, not very: infirme animatus, Cic. Fam. 15, 1, 3.
        Of speech, feebly, without vigor of expression: jejune et infirme, Plin. Ep. 1, 20, 21.
      2. 2. Weak-mindedly, superstitiously: tonitrua et fulgura paulo infirmius expavescebat, Suet. Aug. 9.
    2. B. Form infirmĭter, weakly, feebly, without energy: infirmiter invalideque dicere, Arn. 7, 250.