Lewis & Short

plāco, āvi, ātum, 1, v. a. [etym. dub.; cf.: placeo, planus].

  1. I. To reconcile; constr. alicui, aliquem (class. and freq.): agedum, fac, illa ut placetur nobis, that she be reconciled to us, Ter. Phorm. 5, 3, 1: vereor ut placari possit, id. ib. 5, 8, 72 (cf.: redigam vos in gratiam, v. 73): coeperas eum mihi placare, Cic. Att. 7, 1, 8: rogavit ut te sibi placarem, id. Fam. 13, 1, 3: his vocibus cum in se magis incitarent dictatorem quam magistro equitum placarent, Liv. 8, 33, 1: Hannibalem pater filio meo potui placare, id. 23, 9, 4: placare aliquem rei publicae, Cic. Cat. 2, 8, 17.
    Pass.: quae fuit eorum tanta iniquitas, ut placari populo Romano non possent? Cic. N. D. 3, 6, 15: neque nullam spem habebat, patrem sibi placari posse, Liv. 40, 20, 5.
    In mid. force; usually with in and acc.: numquam animo placari potuit in eum, be reconciled, i. e. consent to a reconciliation, Nep. Pelop. 5, 3; cf. id. Iph. 3, 3: homo quietus et sibi ipsi placatus, at peace with himself, tranquil, Cic. Tusc. 4, 17, 37.
    1. B. In gen., to quiet, soothe, calm, assuage, appease, pacify: animos placare ac lenire, Cic. Fin. 1, 14: placare et mitigare animum, id. Phil. 10, 3, 6: numen deorum immortalium, Caes. B. G. 6, 15: aliquem beneficiis, Liv. 4, 33: iram deorum donis, Cic. Leg. 2, 9, 22: benevolos objurgatores, id. N. D. 1, 3, 5: invidiam, Hor. S. 2, 3, 13.
      Poet.: ventos sanguine, Verg. A. 2, 116: Hippotades cum vult, aequora placet, Ov. M. 11, 432: escā ventrem iratum, Hor. S. 2, 8, 5: sitim, to quench, Mart. 1, 50, 17.
  2. II. To endeavor to appease, Hor. C. 2, 14, 6; Ter. Ad. 1, 2, 64.
    Hence, plācātus, a, um, P. a., soothed, appeased, calmed; quiet, gentle, still, calm, peaceful (class.): animi quietus et placatus status, Cic. Tusc. 5, 6, 16: tranquilla, quieta vita, id. Fin. 1, 21, 71: placidae ac minime turbulentae res, id. Or. 19, 63: maria, Verg. A. 3, 69: vultu ac sermone in omnes placato, Liv. 28, 32, 1.
    Comp.: placatiore animo aliquid facere, Liv. 37, 45; 2, 60: dii, Plin. 12, 18, 41, § 83.
    Sup.: quies placatissima, Cic. Tusc. 1, 41, 97.
    Hence, adv.: plācātē, quietly, gently, calmly, composedly (class.): omnia humana placate et moderate feramus, Cic. Fam. 6, 1, 4.
    Comp.: remissius et placatius ferre, Cic. Fam. 6, 13, 3.