Dictionary.com
Thesaurus.com
Synonyms

faithless

American  
[feyth-lis] / ˈfeɪθ lɪs /

adjective

  1. not adhering to allegiance, promises, vows, or duty.

    the faithless behavior of Benedict Arnold.

  2. not trustworthy; unreliable.

  3. without trust or belief.

  4. being without religious faith.

  5. (among Christians) bereft of Christian faith.


faithless British  
/ ˈfeɪθlɪs /

adjective

  1. unreliable or treacherous

  2. dishonest or disloyal

  3. having no faith or trust

  4. lacking faith, esp religious faith

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Etymology

Origin of faithless

First recorded in 1250–1300, faithless is from the Middle English word faithles. See faith, -less

Explanation

Someone who's faithless can't be trusted to be loyal. The faithless advisor to a king might turn out to be a traitor plotting against him. If you're faithless, you're untrustworthy. You might be a faithless government worker, stealing state secrets to sell to an enemy, or a faithless boyfriend, secretly dating other people behind your girlfriend's back. The earliest meaning of faithless was "lacking religious faith," although it came to mean "deceptive" by the middle of the 14th century. Faith comes from the Latin fides, "trust, faith, or belief."

Keep Reading on Vocabulary.com

Vocabulary lists containing faithless

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.

Dictators may be faithless and brutal to their own people, but in the rarefied circle of fellow dictators, a kind of camaraderie flourishes.

From Salon • Mar. 14, 2026

A lone faithless elector in Washington state made it a three-way race by voting for Ronald Reagan.

From Slate • Aug. 9, 2024

It is a different reality for the openly faithless in southern Nigeria; they even hold public meetings occasionally.

From Seattle Times • Oct. 4, 2023

But in its unexpurgated form, it accurately reflects how women describe their faithless suitors.

From New York Times • Aug. 20, 2021

Day by day, night by night he recedes, and I become more faithless.

From "The Handmaid's Tale" by Margaret Atwood