Lewis & Short

obstĭno, āvi, ātum, 1, v. a. [a lengthened form of obsto], to set about a thing with firmness or resolution, to set one’s mind firmly on, to persist in, be resolved on a thing (as a verb. fin. very rare; only the Part. as a P. a. is freq.).

        1. (α) With acc.: id inhiat, ea affinitatem hanc obstinavit gratia, Plaut. Aul. 2, 2, 89.
          Pass.: obstinari exorsus, Pac. ap. Paul. ex Fest. p. 193 Müll. (Trag. Rel. p. 425 Rib.).
        2. (β) With inf.: obstinaverant animis aut vincere, aut mori, Liv. 23, 29, 7.
        3. (γ) Absol.: ipso Vespasiano inter initia imperii ad obtinendas iniquitates haud perinde obstinante, Tac. H. 2, 84.
          Hence, obstĭnātus, a, um, P. a., firmly set, fixed, resolved, in a good or bad sense; determined, resolute, steadfast, inflexible, stubborn, obstinate (class.; syn.: pervicax, pertinax): vos qui astatis obstinati, Naev. ap. Paul. ex Fest. p. 193 Müll. (Trag. Rel. p. 11 Rib.): obstinato animo aliquid facere, Att. ap. Paul. ex Fest. l. l. (Trag. Rel. p. 123 Rib.); so, Vulg. Ruth, 1, 18: ad decertandum obstinati animi, Liv. 6, 3, 9: ad silendum, Curt. 8, 1, 30: ad mortem, Liv. 5, 41, 1: adversus lacrimas, id. 2, 40, 3; 3, 47, 4: ad resistendum, Suet. Caes. 15 fin.: contra veritatem, Quint. 12, 1, 10: pudicitia, Liv. 1, 58: fides, Tac. H. 5, 5: aures, Hor. C. 3, 11, 7.
          With inf.: jam obstinatis mori spes affulsit, Liv. 42, 65; 7, 21, 1; 9, 25, 6: obstinatum est tibi, non suscipere imperium, nisi, etc., you are firmly resolved, Plin. Pan. 5, 6.
          Rarely with in: obstinatae in perniciem Romae urbes, Amm. 17, 11, 3: in extrema, Tac. H. 3, 56: militum animos obstinatos pro Vitellio subruere, id. H. 2, 101.
          Comp.: voluntas obstinatior, Cic. Att. 1, 11, 1: adversus lacrimas muliebres, firmer, more steadfast, Liv. 2, 40.
          Sup.: virtus obstinatissima, the most resolute, Sen. Ep. 71, 10: rex obstinatissimus, Amm. 17, 14.
          Hence, adv.: obstĭ-nātē, firmly, inflexibly, in a good and bad sense; resolutely, pertinaciously, stubbornly, obstinately (class.): ita me obstinate aggressus, ut, etc., Plaut. As. 1, 1, 10: operam dat, Ter. And. 1, 5, 8: negari, Caes. B. G. 5, 6: magis ac magis induruisse, Plin. Ep. 1, 12, 10.
          Comp.: obstinatius omnia agere, Suet. Caes. 29.
          Sup.: obstinatissime recusare, Suet. Tib. 67.