I. Lit., to deviate from a straight line: “nil ut deliret amussis,” Aus. Idyll. 16, 11; cf. Plin. 18, 20, 49, § 180.—
II. Trop. (cf. Vel. Long. p. 2233 P.), to be crazy, deranged, out of one's wits; to be silly, to dote, rave (class.): “delirat linguaque mensque,” Lucr. 3, 454: “falli, errare, labi, decipi tam dedecet quam delirare et mente esse captum,” Cic. Off. 1, 27, 94; “so with desipere and dementem esse,” id. N. D. 1, 34, 94: Am. Delirat uxor. So. Atra bili percita est, Plaut. Am. 2, 2, 95 sq.: “senex delirans,” Ter. Ad. 4, 7, 43: “morbo delirantes,” Lucr. 5, 1158; cf. “timore,” Ter. Ph. 5, 8, 8: “in extis totam Etruriam delirare,” Cic. Div. 1, 18, 35: “Stertinium deliret acumen,” Hor. Ep. 1, 12, 20.—With acc. respect.: “quicquid delirant reges plectuntur Achivi,” whatever folly the kings commit, id. ib. 1, 2, 14.