treason

The word “treason” means the crime of betraying one's own country, especially by helping its enemies or attempting to overthrow its government. In plain terms, treason is the most serious kind of betrayal — turning against your own country.

“Treason” is pronounced TREE-zuhn (/ˈtɹiː.zən/ in IPA).

Here is “treason” used in a sentence: “He was charged with treason for leaking military secrets to a hostile power.”

“Treason” is a noun.

The word “treason” comes from Latin. From Old French traïson, ultimately from Latin trādō, "to hand over or betray" — the same root as "tradition" and "betray.".

“Treason” is an uncommon word in modern English.

Treason is the crime of betraying one's own country, especially by aiding its enemies or trying to overthrow its government, while sedition refers to inciting rebellion or resistance against authority without necessarily reaching the level of betrayal treason implies. Treason is generally considered the more severe charge because it involves active betrayal rather than mere incitement.

Treason specifically requires betraying one's own country, often by a citizen owing allegiance to it, whereas espionage refers more broadly to spying or secretly gathering information, which can be committed by anyone regardless of nationality. Espionage can be one method by which treason is carried out, but the two terms are not interchangeable.

No, in its proper legal and dictionary sense, treason applies specifically to betraying one's own country, such as by helping its enemies or attempting to overthrow its government. Using 'treason' for betrayal of a company, team, or group is informal or figurative rather than the literal definition.