Definition

Describing someone who is deceitful and untrustworthy, often betraying others' trust.

Example

His perfidious actions led to the downfall of the entire team.

Conversation

Did you hear about that guy who betrayed his friends?

Yeah, I can't believe he was so perfidious after everything we did for him.

It's really shocking how someone can be so untrustworthy.

I know, right? It's hard to believe we ever trusted him at all.

Synonyms & Antonyms

Root Explanation

Perfidious → It is formed from "per-" (meaning through) and "fides" (meaning faith or trust). The word describes someone who is deceitful or untrustworthy, as if they have betrayed the trust placed in them.

Memory Tip

Think of someone who goes 'through' ('per-') the bonds of 'trust' ('fides') — that's why perfidious means deceitful or untrustworthy.

Visually Confused Words