Lewis & Short

col-lăbĕfacto (conl-), āre, v. a., to make to reel, shake, or totter (perh. only in the two foll. exs.): motu collabefactat onus, Ov. F. 1, 566.
Poet. of liquefying metals: rigorem auri, to overpower, subdue, Lucr. 1, 493; cf. collabefio.