I. Act., to deprive of strength, to weaken, enfeeble.
A. Lit.: “legiones,” Tac. A. 15, 10: munimenta madore, Sall. Fragm. ap. Non. 138, 6: “hominem,” Cels. 2, 12.—
B. Trop.
a. To invalidate, disprove, refute: “res tam leves infirmare ac diluere,” Cic. Rosc. Am. 15, 42; “with tollere,” id. N. D. 2, 59, 147; “with frangere,” id. de Or. 131: “fidem testis,” id. Rosc. Com. 15, 45: “fidem alicui,” id. Att. 15, 26. —
b. To annul, make void: “legem,” Liv. 34, 3; Quint. 7, 1, 49: “contractum,” Dig. 49, 14, 46: “graviter ferens aliquid a se factum infirmari,” Vell. 2, 2, 1: “acta illa atque omnes res superioris anni,” Cic. Sest. 18, 40.—
II. Neutr. only in part. pres. as subst.: infirmantes , um, m., the weak, sick, Sulp. Sev. Vit. S. Mart. 18, 5; id. Ep. 2, 12.