nī̆gresco, grŭi, 3, v. inch. n. (usu. ī) [1. niger],
to become black, grow dark (poet. and post-Aug. prose): latices nigrescere sacros, etc., Verg. A. 4, 454: tenebris nigrescere, id. ib. 11, 824: nigrescunt sanguine venae, Ov. A. A. 3, 503: baca incipiens nigrescere, Plin. 15, 1, 2, § 6: nigrescens cutis, id. 26, 1, 5, § 7: nigrescentes dentes, id. 31, 10, 46, § 117: bacae cum jam nigruerint, Col. 12, 48: dies nigrescet, Vulg. Ezech. 30, 18.