What does unfaithfulness mean?
Unfaithfulness is an uncountable noun meaning disloyalty or betrayal, particularly conduct that violates the trust of a spouse or partner. In discussions of marriage and relationships, it commonly refers to adultery or other romantic betrayals. The word can also have a broader sense: failure to remain faithful to a person, promise, professional obligation, standard, or original source. Thus, a version of a story may be described as unfaithful to its original, and a translation may be criticized for departing from the source text. Unfaithfulness is usually more serious than ordinary disagreement or carelessness because it implies a breach of trust or loyalty. Its strong moral connotation makes it especially common in personal, legal, religious, and literary contexts. Although an unusual plural form exists, the word is normally treated as a mass noun and does not change for different instances of disloyalty.
nounDisloyalty or betrayal, especially of a spouse or partner; more broadly, failure to remain true to a person, promise, standard, or original.
- Disloyalty or betrayal, especially of a spouse or partner.
- Failure to adhere faithfully to a person, commitment, standard, or source, as in an inaccurate adaptation or translation.
"After years of marital unfaithfulness, she ended the relationship."
"She left after discovering her husband's repeated marital unfaithfulness."
"The editor criticized the adaptation's unfaithfulness to the source novel."
Rare. The noun is normally uncountable, so the plural is needed only when discussing distinct instances or categories of unfaithfulness.
"The novel explores the different unfaithfulnesses that can arise within a family."
Unfaithfulness is more than a broken promise: it is the erosion of trust in someone or something entrusted to us.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does unfaithfulness come from?
Unfaithfulness was formed in English by adding the noun-forming suffix -ness to unfaithful, which combines the negative prefix un- with faithful. Faithful in turn belongs to the English word family based on faith, a word borrowed into Middle English from Old French foi and ultimately from Latin fides, meaning trust or belief. The production of unfaithfulness followed the established English pattern of turning an adjective into a noun that names the corresponding quality or condition.
Related word forms
How unfaithfulness is actually used
The word is generally uncountable and commonly carries a strongly moral or evaluative connotation. In relationship contexts, it often refers to romantic or sexual disloyalty, but its broader sense can cover any serious betrayal of trust or failure to honor a commitment.