'Treasonous' definitions:

Definition of 'treasonous'

From: WordNet
adjective
Having the character of, or characteristic of, a traitor; "the faithless Benedict Arnold"; "a lying traitorous insurrectionist" [syn: faithless, traitorous, unfaithful, treasonable, treasonous]

Definition of 'Treasonous'

From: GCIDE
  • Treasonous \Trea"son*ous\, a. Treasonable. --Shak. [1913 Webster]
  • The treasonous book of the Court of King James. --Pepys. [1913 Webster]