Lewis & Short

ex-cerno, crēvi, crētum, 3, v. a., to sift out, to separate (perh. not ante-Aug.).

  1. I. In gen.: furfures a farina, Col. 8, 4, 1: frumenta, i. e. to cleanse, id. 2, 20, 5; cf.: caementa cribris, Vitr. 7, 6: ex captorum numero excretos Saguntinos in patriam remisit, Liv. 28, 39, 10; cf.: excernere parvos, Grat. Cyneg. 289: omnem forensem turbam excretam in quatuor tribus conjecit, Liv. 9, 46 fin.
    Part. perf. subst.:
    excreta tritici, what is sifted out, the chaff, Col. 8, 4, 1; 8, 8, 6.
  2. II. In partic.
    1. A. To keep apart, keep away: multi jam excretos prohibent a matribus haedos, Verg. G. 3, 398 Heyne and Forbig. ad loc.
    2. B. To carry off, discharge (from the body): venter excernit mollia, Cels. 2, 8: quae excreturi sumus, id. 4, 1 al.