disloyal

adjective dis·loy·al \(ˌ)dis-ˈlȯi(-ə)l\

: failing to support or be true to someone or something : not loyal or faithful to your friends, family, country, etc.

Full Definition of DISLOYAL

: lacking in loyalty; also : showing an absence of allegiance, devotion, obligation, faith, or support <his disloyal refusal to help his friend>

— dis·loy·al·ly \-ˈlȯi-ə-lē\ adverb

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Origin of DISLOYAL

Middle English, from Anglo-French desleial, desloial, from des- dis- + leal loyal

First Known Use: 15th century

Related to DISLOYAL

Synonyms: faithless, false, fickle, inconstant, perfidious, recreant, traitorous, treacherous, unfaithful, untrue

Antonyms: constant, dedicated, devoted, devout, down-the-line, faithful, fast, loyal, staunch (also stanch), steadfast, steady, true

Synonym Discussion of DISLOYAL

faithless, false, disloyal, traitorous, treacherous, perfidious mean untrue to what should command one's fidelity or allegiance. faithless applies to any failure to keep a promise or pledge or any breach of allegiance or loyalty <faithless allies>. false stresses the fact of failing to be true in any manner ranging from fickleness to cold treachery <betrayed by false friends>. disloyal implies a lack of complete faithfulness to a friend, cause, leader, or country <disloyal to their country>. traitorous implies either actual treason or a serious betrayal of trust <traitorous acts punishable by death>. treacherous implies readiness to betray trust or confidence <a treacherous adviser>. perfidious adds to faithless the implication of an incapacity for fidelity or reliability <a perfidious double-crosser>.