What does faithlessly mean?
Faithlessly is a formal adverb meaning in a manner that lacks loyalty, trustworthiness, or good faith — most often describing betrayal of a promise, oath, marriage, or allegiance. Someone who acts faithlessly breaks faith with those who relied on them: a vassal who deserts a king, a partner who betrays a spouse, or an ally who switches sides at the critical moment. The word carries a strongly negative, morally charged connotation and belongs chiefly to literary, historical, and elevated registers rather than casual conversation. It derives from "faith," via Old French from Latin "fides" (trust, belief), combined with the Old English suffix "-less" and the adverbial "-ly." A secondary, now archaic sense means without religious belief. Related forms include the adjective "faithless" and the noun "faithlessness." Writers reach for it when they want to emphasize not mere unreliability but active betrayal of trust.
In a manner lacking loyalty or good faith; treacherously or unfaithfully, especially in betrayal of a promise, vow, or allegiance.
"The general acted faithlessly, selling the city's defenses to its besiegers."
Formal and literary; connotes deliberate betrayal rather than mere unreliability.
(Archaic) Without religious faith or belief.
"He lived faithlessly, refusing every call to prayer."
Largely obsolete in modern usage.
Faithlessly is built from "faith" plus the Old English suffix "-less" — so at its root, to act faithlessly is simply to be without faith toward someone who trusted you.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of faithlessly
Faithlessly is formed from "faithless" (itself "faith" + the Old English suffix "-less") plus the adverbial suffix "-ly." The root noun "faith" entered Middle English in the thirteenth century from Old French "feit"/"feid" (modern French "foi"), ultimately from Latin "fides," meaning trust, loyalty, or belief. Cognates within English include "fidelity," "infidelity," and "confide," all tracing back to the same Latin root. The word has carried its core sense of acting without loyalty or good faith since its earliest recorded uses, with a once-common religious sense of "without belief" now largely obsolete.
Related word forms
How faithlessly is actually used
Formal and literary in register; rare in everyday speech but common in historical fiction, translations of classical literature, and moral or religious writing. Strongly negative connotation. The sense "without religious belief" is now largely archaic.
Easily confused with faithlessly
"Fecklessly" means ineffectually or irresponsibly (lacking initiative or competence), while "faithlessly" means disloyally or treacherously (lacking fidelity or good faith).