Lewis & Short

dĕ-albo, āvi, ātum, 1, v. a. [albus], to whiten over, to whitewash, to parget, plaster (good prose, but rare): columnas, Cic. Verr. 2, 1, 55 fin. (twice): parietes, Pall. 1, 24, 1; Suet. Gall. 9; Vitr. 7, 4.
Prov.: duo parietes de eadem fidelia, Curius ap. Cic. Fam. 7, 29; v. fidelia.
In eccl. Lat., to purify, cleanse: in sanguine Agni, Vulg. Apoc. 7, 14.
Pass., to be white, Vulg. Psa. 50, 8 al.
Hence, dĕalbātus, a, um, P. a., whitewashed, plastered: sepulchra, Vulg. Matt. 23, 27; cf. August. Conf. 7, 6.