TREASONABLE
faithless, traitorous, unfaithful, treasonable, treasonous
(adjective) having the character of, or characteristic of, a traitor; “the faithless Benedict Arnold”; “a lying traitorous insurrectionist”
Source: WordNet® 3.1
Etymology
Adjective
treasonable (comparative more treasonable, superlative most treasonable)
involving or constituting treason
Synonyms
• seditious
• traitorous
Source: Wiktionary
Trea"son*a*ble, a.
Definition: 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.
Syn.
– Treacherous; traitorous; perfidious; insidious. --
Trea"son*a*ble*ness, n.
– Trea"son*a*bly, adv.
Source: Webster’s Unabridged Dictionary 1913 Edition