Lewis & Short

antĕrĭor, ōris, adj. comp. [ante] (only in late Lat.), that is before, foremost: pars. Amm. 16, 8; 25, 3.
Of time, previous, former, anterior: litterae tuae, Symm. Ep. 6, 59: reges, Sulp. Sev. Hist. Sacr. 1, 52 al.
* Adv.: antĕrĭus, before, Sid. Ep. 2, 9.