Lewis & Short

sorbĭlō, adv. [sorbeo], sippingly; hence, transf., drop by drop, bit by bit (ante-class.): victitare, i. e. poorly, sparely, Plaut. Poen. 1, 2, 185: senectutem ducat usque ad senium sorbilo, Caecil. ap. Fest. p. 339 Müll. (Com. Rel. v. 73 Rib.).