nigreo

nī̆grĕo, ēre, v. n. [1. niger],

• to be black (ante-class.): solis occasu nigret, Pac. ap. Non. 144, 11 (Trag. Rel. v. 88 Rib.): nimbis nigret, opp. splendet, Att. ib. 13 (Trag. Rel. v. 260 Rib.).