noun
1.
Synonyms: treachery , disloyalty, faithlessness, perfidiousness, perfidy, treacherousness
Related Word: deceit, deceitfulness; duplicity; Machiavellianism
Idioms: breach of trust ( or faith)
Contrasted words: allegiance, loyalty
Antonyms: staunchness
2.
Synonyms: sedition , seditiousness
Related Word: disloyalty, treacherousness, treachery; high treason; misprision
Antonyms: allegiance