Synonyms of unfaithful

unfaithful 1 of 2

adjective

ˌən-ˈfāth-fəl 

as in traitorous

not true in one's allegiance to someone or something

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

Synonyms & Similar Words

• traitorous
• unreliable
• false
• faithless
• disloyal
• treacherous
• perfidious
• untrue
• inconstant
• fickle
• recreant
• untrustworthy
• irresponsible
• hesitant
• undependable
• uncertain
• faltering
• irresolute
• uninterested
• dubious
• apathetic
• trustless
• dispassionate
• vacillating
• wavering

Antonyms & Near Antonyms

• faithful
• loyal
• true
• constant
• responsible
• steady
• devout
• steadfast
• reliable
• devoted
• trustworthy
• fast
• dedicated
• dependable
• staunch
• dutiful
• solid
• down-the-line
• trusty
• tried
• unfaltering
• unhesitating
• determined
• resolute
• confirmed
• intent
• tried-and-true
• enthusiastic
• trustable
• inveterate
• passionate
• sworn
• unwavering
• ardent
• fervent
• impassioned
• avid
• fervid
• dyed-in-the-wool

unfaithfulness

2 of 2

noun

1

as in infidelity

lack of faithfulness especially to one's husband or wife

he eventually forgave his wife's unfaithfulness

Synonyms & Similar Words

• infidelity
• adultery
• betrayal
• faithlessness
• disloyalty
• perfidy
• inconstancy
• treachery
• perfidiousness
• falseness
• falsity
• deception
• treason
• duplicity
• lying
• deceit
• double-dealing
• sellout
• double cross

Antonyms & Near Antonyms

• faithfulness
• loyalty
• faith
• fidelity
• devotion
• allegiance
• constancy
• fealty
• steadfastness
• reliability
• devotedness
• dependability
• honesty
• staunchness
• trustworthiness

2

as in betrayal

the act or fact of violating the trust or confidence of another

the jaw-dropping unfaithfulness of the person she had considered her best friend was deeply hurtful

Synonyms & Similar Words

• betrayal
• treachery
• treason
• infidelity
• faithlessness
• disloyalty
• deception
• perfidy
• abandonment
• falseness
• backstabbing
• deceit
• lying
• sellout
• double cross
• falsity
• desertion
• two-timing
• business
• duplicity
• double-dealing
• fraud
• informing
• guile
• trickery
• two-facedness
• snitching
• talebearing

Antonyms & Near Antonyms

• faithfulness
• loyalty
• fidelity
• allegiance
• devotion
• steadfastness
• fealty
• reliability
• trustworthiness
• dependability
• defense
• staunchness
• protection
• shield
• safeguard

3

as in adultery

a sexual encounter or relationship between a married person and someone other than their spouse

there were charges of unfaithfulness on both sides

Synonyms & Similar Words

• adultery
• misconduct
• cheating
• infidelity
• treachery
• affair
• two-timing
• faithlessness
• promiscuity
• disloyalty
• romance
• perfidy
• inconstancy
• love
• infatuation
• criminal conversation
• perfidiousness
• falseness
• intrigue
• free love
• amour
• love affair
• flirtation
• entanglement
• fling
• attachment
• liaison
• passion

Antonyms & Near Antonyms

• fidelity
• faithfulness
• loyalty
• devotion
• allegiance
• dedication
• constancy
• steadfastness
• fealty
• devotedness

Example Sentences

Recent Examples of unfaithful

Adjective

Nyong’o also plays Clytemnestra, the unfaithful wife of Agamemnon, whom Clytemnestra and her lover, Aegisthus, murder. — Encyclopedia Britannica, 1 July 2026

In Strangers on a Train, Rogers played Guy's unfaithful wife, whom Bruno offers to kill. — Emily Blackwood, PEOPLE, 29 June 2026

Noun

Coming to the glum realization that love isn’t outlasting infatuation is trickier to write about than a more incendiary subject like unfaithfulness, but Rodrigo pulls it off. — Chris Willman, Variety, 12 June 2026

According to The Daily Mail, unfaithfulness might have been the cause. — Lizzie Lanuza, StyleCaster, 12 Jan. 2026