vacillo (a scanned long, Lucr. 3, 502), āvi, ātum, 1, v. n. cf. Sanscr. vak-, to roll; vank-, to shake, to sway to and fro; to waddle, stagger, reel, totter, waver, vacillate (class.; a favorite word with Cic.; cf.: nuto, titubo). Lit., of drunken persons: quosdam ex vino vacillantes, quosdam hesternā potatione oscitantes, Cic. Fragm. ap. Quint. 8, 3, 66: videre quosdam ex vino vacillantis, Quint. 11, 3, 165: praepediuntur crure vacillanti, Lucr. 3, 479; cf. Ruhnk. ad Rutil. Lup. 2, 7, p. 164 Frotsch.: in utramque partem toto corpore vacillans, Cic. Brut. 60, 216: arbor ventis pulsa vacillans aestuat, Lucr. 5, 1096; so, ambusta, id. 1, 806: vacillant omnia tecta, id. 6, 575: sub pedibus tellus cum tota vacillat, id. 5, 1236: accepi tuam epistulam vacillantibus litterulis, Cic. Fam. 16, 15, 2.

— Trop., to waver, hesitate, stagger, be untrustworthy, to vacillate: tota res vacillat et claudicat, Cic. N. D. 1, 38, 107: Erotem ad ista expedienda factum mihi videbar reliquisse, cujus non sine magnā culpā vacillarunt, have fallen into confusion, id. Att. 14, 18, 2: justitia vacillat vel jacet potius, id. Off. 3, 33, 118: stabilitas amicitiae vacillat, id. Fin. 1, 20, 66: legio vacillans, wavering in fidelity, id. Phil. 3, 12, 31: γεροντικώτερον est memoriola vacillare, id. Att. 12, 1, 2: partim sumptibus in vetere aere alieno vacillant, are staggering beneath a load of old debts, id. Cat. 2, 10, 21: aegrotat fama vacillans, Lucr. 4, 1124: gentes vacillantes, Vell. 2, 130, 3: cum animus paulum vacillavit, Sen. Ep. 114, 22: testes, qui adversus fidem testationis suae vacillant, audiendi non sunt, Dig. 22, 5, 2: cujus (testis) ita anceps fides vacillat, ib. 48, 10, 27.