com-pĕrĭo, pĕri, pertum, 4, v. a. [root par-, of paro, pario; cf. 2. comparo, and aperio, operio, etc.; by others separated from these words and referred to root per-, of πειράω, peritus, periculum; but cf. Corss. Ausspr. II. 410], lit., to disclose wholly, lay open (a fact), without the access. idea of communicating the thing disclosed (which aperio expresses; v. aperio); to obtain a knowledge of a thing, to find out with certainty, to have or gain certain information, to ascertain, learn, etc. (class. in prose and poetry): certo comperi, Ter. Eun. 5, 1, 9: cum indicia mortis se comperisse manifesto et manu tenere diceret, Cic. Brut. 80, 277: hoc, Nep. Eum. 8, 4: stellarum ortus, Cat. 66, 2: de amore hoc comperit, Ter. And. 1, 3, 6: nihil de hoc (Sullā) consul comperi, Cic. Sull. 31, 86; Sall. J. 68, 1: postquam de scelere filii comperit, Nep. Paus. 5, 3; Suet. Dom. 6 al.
With inf. and acc., Ter. And. 1, 1, 63: posteaquam comperit eum posse vivere, Cic. Rosc. Am. 12, 33: hanc gentem Clusium inde venisse comperio, Liv. 5, 35, 3; Quint. 1, 7, 24: diram qui contudit hydram, comperit invidiam supremo fine domari, * Hor. Ep. 2, 1, 12: ubi comperi ex eis qui, etc., Ter. Heaut. 1, 1, 69: aliquid ex multis, Cic. Clu. 68, 192: ex litteris, Nep. Paus. 4, 5: per exploratores, Caes. B. G. 4, 19; 6, 28; Nep. Alcib. 8, 6: certis auctoribus, Cic. Att. 14, 8, 1: nihil testibus, nihil tabulis, nihil aliquo gravi argumento, id. Clu. 45, 126; Caes. B. C. 2, 37: a quo ut rem gestam comperit, Nep. Dat. 3, 4: quae ex fratre compererat nuntiari regi jubet, Curt. 6, 7, 18: ut postea ex captivis comperit, Caes. B. G. 1, 22; Hirt. B. G. 8, 17; 8, 36.
Cicero, on account of the frequent repetition of the phrase omnia comperi, in the trial of Catiline, was often bantered by his contemporaries; hence: (Clodius) me tantum comperisse omnia criminabatur, Cic. Att. 1, 14, 5; cf. id. Fam. 5, 5, 2.
With depend. question: dolo an vere cunctatus, parum comperimus, Sall. J. 113, 1; 67, 3.