Treasonable (adjective)

Involving or constituting treason; betraying one's country or its government.

Origin:

The word "treasonable" is derived from the word "treason" which means betrayal of one"s country and it has been used since the 14th century.

Examples:

1. The act of spying on one's country is treasonable.
2. He was found guilty of treasonable activities.
3. The treasonable plot was foiled by the authorities.
4. Treasonable conduct is punishable by law.
5. The treasonable behavior was a serious crime.