unfaithful

adjective

un·​faith·​ful ˌən-ˈfāth-fəl 

: not faithful:

a

: not adhering to vows, allegiance, or duty : disloyal

an unfaithful friend

b

: not faithful to marriage vows

suspected her husband of being unfaithful

c

: inaccurate, untrustworthy

an unfaithful copy of a document

unfaithfully

ˌən-ˈfāth-fə-lē 

adverb

unfaithfulness noun

Synonyms

• disloyal
• faithless
• false
• fickle
• inconstant
• perfidious
• recreant
• traitorous
• treacherous
• untrue

Examples of unfaithful in a Sentence

colonists who later proved to be unfaithful to the cause of independence

Recent Examples on the Web

Green asked the reporter, who alleged that the singer was unfaithful to his former fiancée. —Julia Moore, People.com, 13 Dec. 2024

Meanwhile, Lopez confirmed in 2003 that Combs had been unfaithful to her during their relationship, but has rarely ever spoken of him since. —Conor Murray, Forbes, 25 Sep. 2024

In a separate interview, the former NFL player admits that he’s been unfaithful during his relationship with Brown. —Elizabeth Ayoola, Essence, 5 Dec. 2024

News of their breakup came as a shock to most fans, some of whom took to Reddit to share their speculation about the update –– many of whom think Keoghan was unfaithful to the songstress. —Mark R. Weaver, Newsweek, 4 Dec. 2024

Word History

First Known Use

15th century, in the meaning defined above

Kids Definition

unfaithful

adjective

un·​faith·​ful ˌən-ˈfāth-fəl 

ˈən-

1

: not observing vows, allegiance, or duty : disloyal

an unfaithful friend

2

: not faithful to marriage vows

3

: inaccurate

an unfaithful translation

unfaithfully

-fə-lē 

adverb

unfaithfulness noun