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Synonyms

treasonous

American  
[tree-zuh-nuhs] / ˈtri zə nəs /

adjective

  1. treasonable.


Other Word Forms

  • treasonously adverb

Etymology

Origin of treasonous

First recorded in 1585–95; treason + -ous

Explanation

Anything treasonous involves a betrayal, particularly of your country. Your sister might consider it treasonous if you tell your parents she skipped school to go to the beach. When we betray our friends or families, that's personally treasonous. To betray your country is legally treasonous, since it's a punishable crime. It would be treasonous for a CIA agent to hand over U.S. secrets to an enemy spy—and the root of treasonous is the Latin verb tradere, "to hand over or betray."

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Vocabulary lists containing treasonous

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.

It was called “constructive treason,” because there was no act, but courts construed such forms of speech to be treasonous.

From Slate • Nov. 21, 2025

In my America, like Pope Leo’s, speaking multiple tongues and being a citizen of multiple countries is normal, not treasonous — Leo is a dual Peruvian U.S. citizen who speaks five languages.

From Los Angeles Times • May 10, 2025

It’s not at all treasonous to say that one of Thursday’s most potent moments actually came while Queen Bey went off for her final wardrobe change, ceding the spotlight to her battalion of dancers.

From Seattle Times • Sep. 15, 2023

"She achieved fame abroad at a time when this was considered treasonous by the press."

From BBC • Jun. 6, 2023

“I wasn’t involved in any treasonous activity if that’s what you’re asking. He was just a friend, like I said.”

From "In the Time of the Butterflies" by Julia Alvarez