infidelity

noun

in·​fi·​del·​i·​ty ˌin-fə-ˈde-lə-tē 

-(ˌ)fī-

plural infidelities

1

a

: the act or fact of having a romantic or sexual relationship with someone other than one's husband, wife, or partner

b

: unfaithfulness to a moral obligation : disloyalty

2

: lack of belief in a religion

Synonyms

• disloyalty
• faithlessness
• falseness
• falsity
• inconstancy
• perfidiousness
• perfidy
• unfaithfulness

Examples of infidelity in a Sentence

She was convinced that her husband was guilty of infidelity.

He has admitted to a number of marital infidelities.

Recent Examples on the Web

Paquita la del Barrio rose to fame with her anthems about infidelity and heartbreak. —Natalia Cano, Billboard, 21 Feb. 2025

The 27-year-old aired her frustrations out on X on Monday night (Feb. 17), seemingly accusing Trippie Redd of infidelity. —Demicia Inman, VIBE.com, 19 Feb. 2025

After what appeared to be a public display of infidelity by Herbie, Nicole filed for divorce in July 2023. —Kerry A. Dolan, Forbes, 14 Feb. 2025

News of infidelity surfaced, and suddenly, what once seemed unbreakable lay in ruins. —Raul A. Reyes, Newsweek, 22 Jan. 2025

Word History

Etymology

Middle English infidelite, borrowed from Middle French infidelité, borrowed from Latin infidēlitāt-, infidēlitās "faithlessness, inconstancy," from infidēlis "unfaithful, disloyal" + -itāt-, -itās -ity — more at infidel entry 2

First Known Use

15th century, in the meaning defined at sense 2

Rhymes for infidelity

• fidelity

Kids Definition

infidelity

noun

in·​fi·​del·​i·​ty ˌin-fə-ˈdel-ət-ē 

-(ˌ)fī-

plural infidelities

1

: lack of faith in a religion

2

: unfaithfulness especially to one's husband or wife