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Definitions

unfaithful

[uhn-feyth-fuhl] / ʌnˈfeɪθ fəl /
ADJECTIVE
disloyal, adulterous
Synonyms
STRONGEST
cheating untrue
WEAK
adulterine deceitful double-crossing faithless false false-hearted fickle foresworn inconstant incontinent moonlighting not true to of bad faith perfidious philandering recreant shifty snaky sneaking traitorous treacherous treasonable two-faced two-timing unchaste unreliable untrustworthy wicked
Antonyms
WEAK
faithful loyal trustworthy

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.

He denied ever witnessing Epstein in the company of a minor and said he was never unfaithful to his wife.

From The Wall Street Journal • Feb. 18, 2026

"And three months ago, I made the biggest mistake of my life and I was unfaithful," he continued.

From Barron's • Feb. 11, 2026

It’s not that she’s unfaithful to the material.

From Los Angeles Times • Mar. 31, 2025

Ms Trussler said during the trial MacPhail had attempted to portray her "caring, kind daughter" as a "nasty, unfaithful girlfriend" but that "could not be further from the truth".

From BBC • Oct. 31, 2024

This night I would confront him and demand to know with whom he thought I had been unfaithful, and when.

From "Ophelia" by Lisa Klein