Lewis Short
ŏb-ātrātus, a, um
* Adj., obscured, black, blackish: nascens luna si cornu superiore obatrato surget, pluvias decrescens dabit, Varr. ap. Plin. 18, 35, 79, § 349 Sillig. N. cr. (al. obatro).
Charlton T. Lewis, Charles Short, A Latin Dictionary