the quality of being disloyal; lack of loyalty; unfaithfulness.
violation of allegiance or duty, as to a government.
a disloyal act.
Origin: 1400–50;late Middle English < Middle Frenchdesloiaute,Old Frenchdesleaute, equivalent to deslealdisloyal + -te-ty2
Synonyms 1. faithlessness, subversion. Disloyalty, perfidy, treachery, treason imply betrayal of trust. Disloyalty applies to any violation of loyalty, whether to a person, a cause, or one's country, and whether in thought or in deeds: to suspect disloyalty in a friend.Perfidy implies deliberate breaking of faith or of one's pledges and promises, on which others are relying: It is an act of perfidy to cheat innocent people.Treachery implies being secretly traitorous but seeming friendly and loyal: In treachery deceit is added to disloyalty.Treason is performing overt acts to help the enemies of one's country or government: Acting to aid a hostile power is treason.