trĕbax — Lewis & Short
trĕbax, ācis, adj.contr. from the Gr. tribako/s,
I practised, skilled in the ways of the world, cunning, crafty (lat. Lat.):
trebacissimus senex,Sid. Ep. 1, 11 med.—Adv.: trĕbācĭter, cunningly, slyly, Sid. Ep. 9, 11 med.