Webster’s Revised Unabridged Dictionary · 1913
Disloyal
Dis·loy′al (dĭs·loi′al), a. [Pref. dis- + loyal: cf. OF. desloial, desleal, F. déloyal. See Loyal.] Not loyal; not true to a sovereign or lawful superior, or to the government under which one lives; false where allegiance is due; faithless; as, a subject disloyal to the king; a husband disloyal to his wife.
Without a thought disloyal. Mrs. Browning.
Syn. — Disobedient; faithless; untrue; treacherous; perfidious; dishonest; inconstant; disaffected.