O / obreptīvus
adjective

obreptīvus

fem. obreptīva · neut. obreptīvum
secret, clandestine; surreptitiously, clandestinely
secret, clandestine (post-class.): supplicatio, Symm. Ep. 5, 64; Cod. Th. 16, 10, 8.—Hence, adv.: obreptīvē, surreptitiously, clandestinely (post-class.): aut clanculo supplicare, Cod. Th. 16, 1, 4 fin.