Definition of treason in English:



  • 1[mass noun] The crime of betraying one's country, especially by attempting to kill or overthrow the sovereign or government.

    ‘they were convicted of treason’
    • ‘The security laws ban treason, sedition, subversion and the theft of state secrets.’
    • ‘The erstwhile British colonial rulers used the fort to try the freedom fighters after convicting them of treason.’
    • ‘Radical leaders were arrested on charges of high treason after they held a national convention.’
    • ‘She had no idea what she'd done to be charged with a serious crime like treason.’
    • ‘It is the goal of all agents to bravely expose treason and hidden crimes in order to safeguard national security.’
    • ‘Everyone knows that murder and manslaughter, kidnapping and terrorism, treason and high treason existed long before today's penal codes.’
    • ‘Once labelled a terrorist, he was convicted of treason and jailed for 27 years.’
    • ‘Following the overthrow of the Raterepublik, he was indicted for high treason but was subsequently acquitted of all charges.’
    • ‘The charges include treason, conspiracy to commit treason and being accessories to treason.’
    • ‘In times of wars the church stood at the forefront of sedition and treason, unless it saw some advantage for itself.’
    • ‘Franco eliminated universal suffrage and viewed any criticism of the regime as treason.’
    • ‘Equally ominous is the extension of the definition of treason, regarded as one of the most serious political crimes of all.’
    • ‘He said that his lawyer advised him to leave Kenya as it was rumoured that he would soon be charged with sedition and treason.’
    • ‘It is absolutely out of order to suggest that an honourable member of this House is committing treason.’
    • ‘In some other countries that would be called treason or treachery.’
    • ‘Sacrificing you, or simply having you killed for treason, would have only led to more conflict.’
    • ‘Military officials initially told the press that he might face charges of espionage and sedition, even treason.’
    • ‘To resist the will of the sovereign was treason, and to avoid exile, or even the block, it was necessary to tread carefully.’
    • ‘Prosecutors are demanding life sentences for five suspected militants charged with a crime similar to treason.’
    • ‘Duress has been recognised as a general defence to all crimes except treason and murder.’
    treachery, lese-majesty
    disloyalty, betrayal, faithlessness, perfidy, perfidiousness, duplicity, infidelity
    sedition, subversion, mutiny, rebellion
    high treason
    punic faith
    View synonyms
    1. 1.1The action of betraying someone or something.
      ‘doubt is the ultimate treason against faith’
      • ‘Our ways of saying ‘I’ and ‘me’ and ‘my’ express our ultimate treasons and devotions.’
      • ‘God defend your Church from the treasons of men.’
      • ‘African-Americans, it is cynically assumed, will remain loyal to the Democrats regardless of the treasons committed against them.’
      • ‘‘The man that hath no music in himself’ (says the Bard), ‘is fit for treasons, stratagems and spoils… Let no such man be trusted.’’
      treachery, lese-majesty
      disloyalty, betrayal, faithlessness, perfidy, perfidiousness, duplicity, infidelity
      sedition, subversion, mutiny, rebellion
      high treason
      punic faith
      View synonyms
    2. 1.2historical The crime of murdering someone to whom the murderer owed allegiance, such as a master or husband.
      • ‘One newspaper said he looked like a horrid wretch, ‘fit evidently for petty treason.’’
      • ‘A wife who killed her husband did not commit murder - she committed the far worse crime of petty treason.’
      • ‘Perhaps as a consequence, the year 1352 saw the introduction of the Statute of Treasons defining great treason against the king and petty treason against local lords.’
      • ‘Ms Pritchard, my recollection is that a woman charged with murdering her husband, at one stage of the common law, was charged with petty treason and it was heard by a jury of 24.’


Formerly, there were two types of crime to which the term treason was applied: petty treason, the crime of murdering one's master, and high treason, the crime of betraying one's country. The crime of petty treason was abolished in 1828 and in modern use high treason is often simply called treason


Middle English: from Anglo-Norman French treisoun, from Latin traditio(n-) handing over, from the verb tradere.