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Perfidiousness

Noun | /perfidiousness/

Advanced WordsVERY HARD

The quality or conduct of being deceitful and disloyal, especially toward someone who trusts you.

Learning Progress

Synonyms

treacherydisloyaltydeceitfulness

Antonyms

loyaltyfaithfulness

Examples

"The treaty collapsed after the allies condemned the ruler’s perfidiousness. Means: The allies condemned the ruler’s betrayal and deceit, and the treaty fell apart."

"The story portrays the minister’s perfidiousness as a turning point in the kingdom’s history. Means: The story presents the minister’s treacherous conduct as a crucial event in the kingdom’s history."

Mnemonic Trick

Perfidiousness is the quality of breaking faith with someone who trusts you.

Source: Advanced WordsAdded: 9/29/2026

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