# treasonous

/ˈtɹizəˌnəs/ (US) · /tɹˈiːzənəs/ (UK) · CEFR C1 · Adjective

Source: https://englishreference.com/word/treasonous
Updated: 2026-10-13

## Definition

acting against your own country, like helping its enemies or trying to remove its government. You use it for actions, plans, or words that betray the country.

For teachers: involving or constituting betrayal of one's sovereign state, typically by aiding its enemies or attempting to overthrow its government. Often applied to acts, statements, or intentions that violate allegiance to the state.

## Examples

- They call his speech treasonous and demand his arrest.
- The newspaper accused the officer of treasonous behavior after he shared secret maps with a foreign army.
- Historians still debate whether her letters to the exiled prince were merely sympathetic or actively treasonous in intent.

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