Lewis & Short

1. obsĕro, āvi, ātum, 1, v. a. [ob-sera], to bolt, bar, fasten, or shut up (not in Cic. or Cæs.; syn.: claudo, oppilo, obstruo).

  1. I. Lit.: ostium, Ter. Eun. 4, 6, 25: aedificia, Liv. 5, 41: fores (opp. aperire), Suet. Tit. 11: tabellam liminis, Cat. 32, 5: exitus, Col. 9, 1, 3: rogos, i. e. the dead, Prop. 4, 11, 8.
  2. II. Transf.: aures, Hor. Epod. 17, 53: palatum (for os), i. e. to be silent, Cat. 55, 21: fores amicitiae, Amm. 27, 12.

2. ob-sĕro (ops-), sēvi, sĭtum, 3 (inf. perf. sync. obsesse for obsevisse, Att. ap. Non. 395, 27), v. a.

  1. I. Lit.
    1. A. To sow or plant (class.): frumentum, Plaut. Trin. 2, 4, 129.
      Comically: pugnos, to give a good drubbing, Plaut. Men. 5, 7, 23.
    2. B. Transf.
      1. 1. To sow or plant with any thing: saepimentum virgultis aut spinis, Varr. R. R. 1, 14, 1: terram frugibus. Cic. Leg. 2, 25, 63; Col. 2, 9, 1; Varr. R. R. 1, 44, 2.
      2. 2. In gen., to cover over, fill with; only in perf. pass. part., covered over, filled: omnia arbustis obsita, Lucr. 5, 1377: loca obsita virgultis, Liv. 28, 2: obsita pomis Rura, Ov. M. 13, 719: video aegrum pannis annisque obsitum, Ter. Eun. 2, 2, 5: obsitus illuvie ac squalore, Tac. A. 4, 28: vestis obsita squalore, Liv. 2, 23: legati … obsiti squalore et sordibus, id. 29, 16: variis obsita frondibus, Hor. C. 1, 18, 12: montes nivibus, Curt. 5, 6, 15: aër pallore, darkened, Luc. 5, 627; cf.: dies nube obsitus, Sen. Troad. 20: obsitus aevo, Verg. A. 8, 307: Io jam setis obsita, id. ib. 7, 790: terga (marinae beluae) obsita conchis, Ov. M. 4, 724.
  2. II. Trop.: Tun’ is es, qui in me aerumnam obsevisti, hast brought upon me, occasioned me, Plaut. Ep. 4, 1, 30: em istic oportet opseri mores malos, si in opserendo possint interfieri, id. Trin. 2, 4, 130.