Lewis Short
(adjective) : trĕbax, ācis, contr. from the Gr. τριβακός
* 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.
Charlton T. Lewis, Charles Short, A Latin Dictionary