Lewis & Short

ob-mōlĭor, ītus, 4, v. dep. (perh. not ante-Aug.).

  1. I. Lit., to push or throw up one thing before another (as a defence or obstruction): nec in promptu erat quod obmolirentur, Liv. 33, 5, 8: arborum truncos et saxa, Curt. 6, 6, 24.
  2. II. Transf., to block up, obstruct: ad munienda et obmolienda, quae ruinis strata erant, Liv. 37, 32, 7; cf. id. 33, 5.