vespĕrasco — Lewis & Short
vespĕrasco, āvi, 3,
I v. inch. n. [vesper], to become evening, grow towards evening:
vesperascente jam die,Tac. A. 16, 34:
vesperascente caelo,Nep. Pelop. 2, 5.—Impers.:
vesperascit,Ter. Heaut. 2, 3, 7:
ubi jam vesperaverat,Gell. 17, 8, 1.