Disloyal

прилагательное 1) нелояльный, неблагожелательный 2) вероломный, изменнический, предательский, неверный Например: disloyal wife — неверная жена Синоним(ы): unfaithful, faithless, perfidious, treacherous

Большой англо-русский словарь

Disloyal

adjective Etymology: Middle English, from Anglo-French desleial, desloial, from des- dis- + leal loyal lacking in loyalty; also showing an absence of allegiance, devotion, obligation, faith, or support Example: his disloyal refusal to help his friend Synonyms: see faithlessdisloyally adverb

Merriam-Webster's Collegiate Dictionary