Trêa'son-a-ble, a.

(trē'zn-a-bl), a. Pertaining to treason; consisting of treason; involving the crime of treason, or partaking of its guilt.

Most men's heads had been intoxicated with imaginations of plots and treasonable practices. Clarendon.

Synonyms—Treacherous; traitorous; perfidious; insidious.