Lewis & Short

lēvor (laevor), ōris, m. [2. levis], smoothness: haud sine principali aliquo levore, Lucr. 2, 423: spectantur in chartis tenuitas, densitas, candor, levor, Plin. 13, 12, 24, § 78: levorem corpori afferre, id. 30, 14, 43, § 127; 37, 4, 15, § 56: vocis, Lucr. 4, 552.