Lewis & Short

prōverbĭālis, e, adj. [proverbium], proverbial (post-class.): versus, Gell. 2, 22, 24.
Adv.: prōverbĭālĭter, proverbially, Amm. 29, 2, 25; Sid. Ep. 7, 9; Don. ad Ter. Eun. 2, 2, 37.