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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.

Once the Games began, they were humiliated again by another kind of cheating scandal involving an unfaithful biathlete.

From The Wall Street Journal • Feb. 17, 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

The term “homewrecker” makes my skin crawl — probably because my dad was serially unfaithful to my mom, which I knew about for two reasons.

From Los Angeles Times • Mar. 22, 2024

The ex-Celtic and Hibs striker, 35, repeatedly messaged Eilidh Scott accusing her of being unfaithful and questioning her ability as a mother.

From BBC • Mar. 15, 2024

I was not going to be accused of being unfaithful.

From "Dragonwings" by Laurence Yep