Lewis & Short

grassor, ātus, 1 (inf. pres. grassarier, Prud. Ham. 651; act. collat. form grassabamus, App. M. 7, 7), v. dep. n. and a. [gradior], to go, go about (not in Cic. and Cæs.; cf.: gradior, incedo, vado, pergo).

  1. I. Lit.
    1. A. In gen. (mostly ante-class.): hoc grassari gradu, Plaut. Poen. 3, 1, 11: siccine hic cum uvida veste grassabimur? id. Rud. 1, 4, 31; id. Bacch. 5, 2, 19: sine eam pedibus grassari, Titin. ap. Non. 316, 3: recte grassatur via, Nov. ib. 5; Ov. Tr. 2, 477: certum’st moriri, quam hunc pati grassari lenonem in me, come about me, approach me, Plaut. Rud. 3, 3, 22.
        1. b. Of things: (aranĕus) quanta arte celat pedicas scutulato rete grassantes, going about, moving around, Plin. 11, 24, 28, § 81: per omnes nervos articulosque humore pestifero grassante, Just. 23, 2: neque avaritia solum, sed etiam crudelitas in capta urbe grassata est, Curt. 5, 6, 6.
    2. B. In partic.
      1. 1. To go loitering or rioting about (cf. grassator, I.): se in juventutem grassantem in Subura incidisse, Liv. 3, 13, 2: per omnia clandestina grassari scelera latrociniorum, id 42, 18, 1: ubi Caesarem esse qui grassaretur pernotuit, Tac. A. 13, 25.
        Hence, of parasites, i. q. adulari, to pay one’s court to, to flatter, fawn upon: grassari antiqui ponebant pro adulari, Paul. ex Fest. p. 97 Müll.
      2. 2. To go about with thievish designs, to lie in wait: grassari dicuntur latrones vias obsidentes, Paul. ex Fest. p. 97 Müll. (cf. grassator, II.): in umbris, Anthol. Lat. 2, 186, 42 sq.: silurus grassatur, ubicumque est, omne animal appetens, Plin. 9, 15, 17, § 45.
        Hence,
        1. b. With acc., to fall upon, assault, attack: turmas, Stat. Th. 8, 571.
  2. II. Trop.
    1. A. In gen., to go, proceed, or act in any manner: saepe hac eadem sum grassatus via, Nov. ap. Non. 316, 7; cf.: consimili grassantur via, Afran. ib. 9: ubi animus ad gloriam virtutis via grassatur, Sall. J. 1, 3: grassandum ad clara periclis, Sil. 1, 570: (assertor) ait, se jure grassari, non vi, that he was proceeding, Liv. 3, 44, 8: longe alia via grassabantur, id. 2, 27, 7: consilio grassandum, si nihil vires juvarent, ratus, id. 10, 14, 13: mutua dissimulatione et iisdem, quibus petebatur, artibus grassatur, Tac. H. 4, 56: cupidine atque irā, pessimis consultoribus, Sall. J. 64, 5: obsequio, to act obsequiously, Hor. S. 2, 5, 93: dolo, to act cunningly, Tac. H. 4, 16: assentando multitudini grassari, Liv. 45, 23, 9: superbe avareque in provincia grassatos, Suet. Aug. 67.
    2. B. In partic., to attack, proceed against; to proceed with violence, act harshly, rage, rage against.
      Constr.: in aliquid and in or adversus aliquem: trecenti conjuravimus principes juventutis Romanae, ut in te hac via grassaremur, Liv. 2, 12, 15; cf.: in possessionem agri publici grassari, id. 6, 5, 4: in externos grassari, Suet. Ner. 36: adversus omnis aevi hominum genus grassari, id. Calig. 34; cf.: qui cum contemptu religionis grassatus etiam adversus deos fuerat, Just. 1, 9: ita bacchantem atque grassantem adoriri, Suet. Calig. 56: omni rapinarum genere grassati, id. Vesp. 6: diverso vitiorum genere, id. Galb. 14; cf.: placuit veneno grassari, Tac. H. 3, 39; id. A. 15, 60.
      Absol.: Ii (sagitarii) dum eminus grassabantur, Tac. A. 4, 47.
      Of abstract subjects: accusatorum major in dies et infestior vis sine levamento grassabatur, Tac. A. 4, 66: ut clausis unam intra domum accusatoribus et reis, paucorum potentia grassaretur, id. ib. 13, 4: dicemus de his (malis), quae totis corporibus grassantur, Plin. 26, 11, 67, § 107; cf.: haec (vitia) in pueris grassari, illa in adultis, id. 26, 1, 3, § 4: mala vestra, … alia grassantia extrinsecus, alia in visceribus ipsis ardentia, Sen. Vit. B. 27, 6: rabidorum more luporum Crimina persultant toto grassantia campo, Prud. Psych. 468: grassandi in re familiari facultas, of wasting, plundering, Dig. 26, 10, 6.
      Fig.: nec ferro grassatur saepius ullum mentis vitium quam cupido, etc., Juv. 14, 174.
        1. b. With acc. (cf. above, I. B. 2. b.): simulque Romam pestilentia grassabatur, Aur. Vict. Caes. 33, 5.
          P. a.: grassans, ntis, m., as subst., a robber, thief: quicquid Lycurgi villa grassantibus praebuisset, Petr. 117, 3; App. M. 8, p. 209, 3: sublatis susceptoribus grassantium cupido conquiescit, Paul. Sent. 5, 3, 4.