frustrā (-tră, Prud. στεφ. 1, 13), adv. orig. acc. plur. neutr., afterwards abl. sing. fem. of frusterus, for frud-; v. fraus; hence. In deception, in error (so mostly anteclass. and in historians; not in Cic. and Caes.): ambo, et servus et era, frustra sunt duo, Qui me Amphitruonem rentur esse: errant probe, are deceived, in error, Plaut. Am. 3, 3, 19; cf. id. Bacch. 4, 7, 42: nunc, mulier, nei frustra sies, mea non es: ne arbitrere, id. Merc. 3, 1, 30: quo mihi acrius annitendum est, ut neque vos capiamini, et illi frustra sint, Sall. J. 85, 6: frustra esse, Plaut. Capt. 4, 2, 74: hilarus est; frustrast homo, id. Most. 3, 1, 40 Lorenz: ne frustra sis, id. Men. 4, 3, 18 sq.; id. Mil. 5, 29 al.; cf. in the foll. II. A.—With animi: erras, Aemiliane, et longe hujus animi frustra es, App. Mag. p. 286.—Frustra habere aliquem, to deceive, cheat one (= eludere): Corbulo quaesito diu proelio frustra habitus, Tac. A. 13, 37; 51: si Persae frustra habitae redissent ad sua, Amm. 18, 6, 6: servom ac dominum, Plaut. Am. argument. 5.— Transf., according as particular respect is had to the effect, the aim, or the reason of an action, without effect, to no purpose, without cause, uselessly, in vain, for nothing (freq. and class.; the predom. signif. in prose and poetry; cf.: in cassum, nequiquam). Without effect, in vain: alii parasiti frustra obambulabant in foro, i. e. they got no dinner, Plaut. Capt. 3, 1, 31: praesagibat mihi animus, frustra me ire, quom exibam domo, id. Aul. 2, 2, 1: nemo dabit; frustra egomet mecum has rationes puto, Ter. Ad. 2, 2, 53: frustra operam opinor sumo, id. Heaut. 4, 3, 15: neque ipse auxilium suum saepe a viris bonis frustra implorari patietur, Cic. de Or. 2, 33, 144: haec si verbis explicare conemur, frustra suscipiatur labor, id. Univ. 10: fortissima frustra pectora, Verg. A. 1, 348; 5, 389: multum frustraque rogatus, Luc. 4, 735: peritura frustra agmina, id. 7, 736; Ov. M. 8, 140: frustra telum mittere, Caes. B. G. 3, 4, 2; cf. id. ib. 3, 25, 1: frustra tantum laborem sumere, id. ib. 3, 14, 1: cujus neque consilium neque inceptum ullum frustra erat, Sall. J. 7, 6 Kritz.; ib. 14, 11 Dietsch; 61, 1; 71, 5; 73 fin. al.; cf.: ita frustra id inceptum Volscis fuit, Liv. 2, 25, 2: neque frustrabor ultra cives meos, neque ipse frustra dictator ero, id. 2, 31, 10; Quint. 10, 1, 2: frustra cruento Marte carebimus, frustra metuemus Austrum: Visendus ater Cocytus, etc., Hor. C. 2, 14, 13 and 15: nam frustra vitium vitaveris illud, si te alio pravum detorseris, id. S. 2, 2, 54: tam frustra (expressere) quam recusaverat (= aeque frustra fuit et sine eventu), likewise without effect, Tac. H. 2, 90 fin. (see the passage in conn.).—With nequiquam, Cat. 77, 1; App. M. 8, p. 208, 40.—With sic: ego astabo hic tantisper cum hac forma et factis sic frustra; cf. Gr. οὕτως ἄλλως, Plaut. Mil. 4, 2, 30.—In a pun with frustra esse (v. supra, I.) and frustrari: qui lepide postulat alterum frustrari, quom frustra'st, frustra illum dicit frustra esse. Nam qui se frustrari quem frustra sentit, Qui frustratur, frustra'st, si ille non est frustra, Enn. ap. Gell. 18, 2, 7 (Sat. 33, p. 158 sq. Vahl.).— Ellipt.: equites et auxiliarios pedites in omnes partes mittit ... Nec frustra. Nam, etc., Hirt. B. G. 8, 5, 3; so, frustra: nam, etc., Hor. C. 3, 7, 21; Flor. 4, 11, 9.— Without reason or cause, groundlessly: frustra ac sine causa quid facere indignum deo est, Cic. Div. 2, 60, 125: frustra tempus contero, id. Rosc. Com. 14, 41: quae disputatio ne frustra haberetur, id. Rep. 1, 7: quae (res) prima impulit etiam, ut suspiceremus in caelum nec frustra siderum motus intueremur, id. ib. 3, 2; 4, 3; id. Tusc. 1, 10, 21; id. Fin. 2, 12, 36; v. Madv. ad h. l. p. 210: non igitur frustra Plato civili viro, quem πολιτικόν vocant, necessariam musicen credidit, Quint. 1, 10, 15; 10, 1, 56: ut multi, nec frustra, opinantur, Suet. Oth. 9: ne quid inexpertum frustra moritura relinquat, Verg. A. 4, 415 Forbig. ad loc.— Ellipt.: hanc quidam aposiopesin putant. Frustra. Nam, etc., Quint. 9, 3, 60.