Lewis & Short

praedĭātor, ōris, m. [praedium], a purchaser of mortgaged estates sold at auction, a dealer in landed estates, Cic. Att. 12, 14, 2; 12, 17: qui mercatur a populo praediator appellatur, Gai. Inst. 2, 61. Persons who followed this business were familiar with mercantile law, and were often consulted as lawyers, Cic. Balb. 20, 45; Dig. 23, 3, 54 in lemm.: praediator, ὠνητὴς ὑπαρχόντων, Gloss. Philox.