treason
Americannoun
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the offense of acting to overthrow one's government or to harm or kill its sovereign.
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a violation of allegiance to one's sovereign or to one's state.
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the betrayal of a trust or confidence; breach of faith; treachery.
noun
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violation or betrayal of the allegiance that a person owes his sovereign or his country, esp by attempting to overthrow the government; high treason
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any treachery or betrayal
Synonym Usage
Treason, sedition mean disloyalty or treachery to one's country or its government. Treason is any attempt to overthrow the government or impair the well-being of a state to which one owes allegiance; the crime of giving aid or comfort to the enemies of one's government. Sedition is any act, writing, speech, etc., directed unlawfully against state authority, the government, or constitution, or calculated to bring it into contempt or to incite others to hostility, ill will or disaffection; it does not amount to treason and therefore is not a capital offense. See disloyalty.
Other Word Forms
Etymology
Origin of treason
First recorded in 1175–1225; Middle English tre(i)so(u)n, from Anglo-French; Old French traïson, from Latin trāditiōn-, stem of trāditiō “delivery, transfer, betrayal”; see tradition
Compare meaning
How does treason compare to similar and commonly confused words? Explore the most common comparisons:
Explanation
Hacking your brother’s email account and sharing all his secrets with your mom could be considered an act of personal treason, meaning you have betrayed your brother. The word treason can be traced back to the Latin word traditio(n-), which comes from the verb tradere, meaning "to hand over, betray." If you commit treason, that’s what you do: you betray. The word is typically used to refer to the betrayal of a government or a country, like when a spy shares national secrets with another country, but it can be used to refer to personal betrayals as well.
Vocabulary lists containing treason
"Macbeth" Vocabulary from Act I
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Liberty, Equality, Vocabulary: The French Revolution
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"The Hunger Games" Vocabulary from Chapter 1
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The American Framers repeatedly mentioned corruption as being, next to treason, the most necessary ground for presidential impeachment.
From Slate ● Oct. 30, 2026
Another potential flashpoint is the treason trial of opposition leader Tundu Lissu, whose verdict is due on November 6.
From Barron's ● Oct. 29, 2026
Former German spy chief August Hanning has been arrested on suspicion of espionage, treason and obtaining classified information for a foreign power, the German Federal Prosecutor's Office says.
From BBC ● Oct. 6, 2026
Sources could be accused of violating censorship laws—or, worse, committing treason.
From The Wall Street Journal ● Sep. 25, 2026
“But Novis, if I find out you helped her in any way, or obstructed my investigation in any way, you’ll be guilty of treason in time of war.”
From "The Bletchley Riddle" by Ruta Sepetys and Steve Sheinkin
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Get a wordDefinitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.