Treason

n. betrayal; the offense of trying to overthrow one's government or harm its leader

For other uses, see Treason (disambiguation) or Traitor (disambiguation). In law, treason is the crime that covers some of the more serious acts of disloyalty to one's sovereign or nation. A person who commits treason is known as a traitor. Oran's Dictionary of the Law (1983) defines treason as: "...[a]...citizen's actions to help a foreign government overthrow, make war against, or seriously injure the [parent nation]." In many nations, it is also often considered treason to attempt or conspire to overthrow the government, even if no foreign country is aided or involved by such an endeavour.
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Noun
1. a crime that undermines the offender's government
(synonym) high treason, lese majesty
(hypernym) crime, law-breaking
2. disloyalty by virtue of subversive behavior
(synonym) subversiveness, traitorousness
(hypernym) disloyalty
(hyponym) betrayal
3. an act of deliberate betrayal
(synonym) treachery, betrayal, perfidy
(hypernym) dishonesty, knavery
(hyponym) double cross, double-crossing

(n.)
The offense of attempting to overthrow the government of the state to which the offender owes allegiance, or of betraying the state into the hands of a foreign power; disloyalty; treachery.
  

(n.)
Loosely, the betrayal of any trust or confidence; treachery; perfidy.
  

To aid or enlist with a state enemy or to attempt or conspire to harm the head of state, such as a king, queen or president. - (read more on Treason)