What does treasonous mean?
Treasonous is an adjective meaning disloyal in a way that resembles treason, especially by betraying one’s country, ruler, or government. Its use is strongly condemnatory and generally formal, making it more pointed than simply negative or unkind criticism. The word is especially appropriate for describing rebellion, attempted overthrow, collaboration with an enemy, or conduct that undermines public authority. In literary and historical contexts, it can be applied more broadly to actions that betray an entrusted trust, though its central association remains with political disloyalty. Treasonous is related etymologically and semantically to words such as treason, traitor, and treacherous. Because it carries serious legal and moral overtones, it is normally reserved for especially grave conduct rather than ordinary disagreement, opposition, or criticism.
adjectiveHaving the character of treason; disloyal to one's country, ruler, or government, especially by attempting to betray or overthrow them.
- Having the character of treason; disloyal to one's country or ruler, especially by attempting to betray or overthrow them.
"The governor condemned the treasonous attempt to seize the border crossing."
"The court described the testimony as treasonous and rejected it as unreliable."
"In the play, the ambassador delivers a treasonous warning to the enemy."
Treasonous is more than a synonym for evil: it names disloyalty directed at the authority or country a person has sworn to serve.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does treasonous come from?
Treasonous was formed in English by adding the suffix “-ous” to treason. Treason developed through Anglo-French and Old French from a Latin word associated with handing over or surrender, reflecting the idea of betrayal. The same broad root underlies cognate English words including traitor, treachery, and treacherous.
Related word forms
How treasonous is actually used
Treasonous is a formal and strongly condemnatory word. It most commonly describes conduct involving betrayal of a country, ruler, or government, but can also be used more broadly for profound disloyalty toward an organization or individual.
Easily confused with treasonous
Treasonous describes a disloyal or betrayal-like quality, whereas treasonable more specifically refers to conduct that may constitute treason.