Lewis & Short

prae-grăvis, e, adj., very heavy (mostly poet. and in post-Aug. prose).

  1. I. Lit.: praegrave onus, Ov. H. 9, 98: caput, Plin. 8, 21, 32, § 77: unda, Mart. 4, 18, 4: perdix feta praegravem aut delumbem esse simulans, heavy, clumsy, Plin. 10, 33, 51, § 103: praegravis corpore, Liv. 44, 4, 10: cibo vinoque praegraves, Tac. H. 2, 21.
  2. II. Trop., very heavy, oppressive, burdensome: praegraves pavonum greges, i. e. very expensive, Varr. ap. Non. 440, 14 (al. graves): tertium consulatum ut praegravem recusare, Plin. Pan. 57, 4: servitium, id. 7, 8, 6, § 46.
    Of persons, very wearisome (Tacitean): delatores, Tac. A. 4, 71: vir principi praegravis, id. ib. 11, 19; 14, 3.