Lacking natural affection for or loyalty towards one's country, unpatriotic; disloyal to one's sovereign or leader; rebellious, treasonable. Obsolete.

Full of treason; treasonous; treacherous.

Of the nature of treason; characteristic of or involving treason; perfidious, treacherous. (Originally Scottish)

Full of or abounding in treason; characterized by treason or treachery; treasonable.

Involving or relating to betrayal of one's country. Later also: that kills his or her father; involving or of the nature of patricide.