What does treachery mean?
Treachery is an uncountable noun meaning betrayal of trust, loyalty, or confidence. It commonly describes someone breaking an obligation to a person, institution, or shared cause, as in an accusation of political treachery or an act of treachery within an organization. The word may also refer broadly to deceitful conduct. Its strong emotional and moral force makes it especially common in formal writing, political discussion, literature, and accounts of political or military history. Treachery is more specific than simple dishonesty because it suggests a violation of an existing bond of trust. Related forms include the adjective treacherous and the adverb treacherously. Although plural forms such as “treacheries” are grammatically possible, the word is normally used in the singular or as an uncountable mass noun.
nounBetrayal of trust or loyalty, especially in a relationship, political group, or position of duty. It can also refer more broadly to deceitful or treacherous conduct.
- Betrayal of trust, loyalty, or confidence, especially by someone entrusted with a duty or relationship.
- Deceitful or treacherous conduct generally.
"Her treachery cost him both his position and the trust of his closest allies."
"The opposition accused the minister of treachery after he shared confidential information with a rival."
"The novel explores treachery in a family where every secret threatens to destroy the remaining relationships."
Possible but uncommon; treachery is normally used as an uncountable noun or in the singular.
"The accounts describe a series of political treacheries that divided the family."
Treachery is betrayal in a single word: it names not merely deception, but deception that violates a bond of trust.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does treachery come from?
The word entered English during the late Middle English period from Old French trecherie, formed from trecher, meaning “to betray.” The related forms treacherous, treacherously, and treacherousness continue the same Old French root, while treach survives as an archaic English verb. The deeper medieval Latin source of trecher is uncertain, so it should not be confidently identified with a particular classical Latin verb.
Related word forms
How treachery is actually used
Usually formal and strongly disapproving. It is common in political, literary, military, and historical contexts, and often implies betrayal of a person or an established duty rather than ordinary dishonesty.
Easily confused with treachery
Treachery is the noun for betrayal or deceit, whereas treacherous is the adjective describing a person or action characterized by treachery.