not loyal (to a person, one's country etc)

unfaithful

guilty of mutiny; rebellious

rebellious

taking part in a rebellion; not easily controlled

disobedient, unmanageable

false or disloyal (to a friend, cause etc); dangerous, severe

dishonest, disloyal

not true (to one's duty, a promise etc); committing adultery

disloyal, adulterous

not patriotic

disloyal