Definition and pronunciation
fidelity /fɪˈdɛləti/ — noun: faithfulness or loyalty to a person, promise, duty, or original source; also, the degree of accuracy with which something is reproduced (as in audio or data fidelity).
Easy explanation
Fidelity means being loyal and keeping your promises. It can describe staying faithful to a partner or making an exact copy of something (like high-fidelity sound or a faithful translation).
Grammatical formation
- Part of speech: uncountable (general quality), sometimes countable in technical uses (“signal fidelities”).
- Common modifiers: marital fidelity, sexual fidelity, absolute fidelity, high-fidelity, low-fidelity.
- Related forms: faithful (adj.), faithfully (adv.), faithfulness (n.), infidelity (opposite), hi-fi/lo-fi (compounds), high-fidelity prototype (UX).
Meanings and nuances
- Loyalty or faithfulness to a person, promise, or principle (“fidelity to one’s spouse,” “fidelity to the facts”).
- Accuracy or exactness in reproduction or representation (“high-fidelity audio,” “fidelity of the model to real-world data”).
- Customer or brand loyalty in business contexts (“customer fidelity”)—less common than “loyalty.”
With prepositions
- fidelity to someone/something: the standard pattern (“fidelity to a spouse,” “fidelity to the source text”).
- fidelity in a role or action: stresses performance (“fidelity in reporting”).
- with fidelity: adverbial sense of accuracy (“reproduced with fidelity”).
- fidelity of X: attributes accuracy to a thing (“the fidelity of the simulation”).
Common collocations
marital fidelity, sexual fidelity, fidelity to a spouse, fidelity to the truth, fidelity to the original, fidelity to one’s vows, high-fidelity audio, low-fidelity mockup, high-fidelity prototype, data fidelity, image fidelity, fidelity bond (insurance), fidelity test, fidelity guarantee
Idioms and neighboring expressions
keep faith, keep one’s word, true to one’s word, stand by, faithful to, tried and true, high-fidelity (hi-fi), low-fidelity (lo-fi)
Word comparisons
- fidelity vs faithfulness: near-synonyms; fidelity is slightly more formal.
- fidelity vs loyalty: loyalty suggests allegiance/attachment; fidelity adds the idea of keeping promises or exact correspondence.
- fidelity vs accuracy: in technical contexts, fidelity overlaps with accuracy but emphasizes closeness to the original signal or source.
- fidelity vs monogamy: monogamy is a relationship structure; fidelity is keeping agreed commitments within any structure (monogamous or consensually non-monogamous).
- fidelity vs integrity: integrity is moral wholeness; fidelity is faithfulness to commitments or originals.
Real-life examples
- “They set their own boundaries for fidelity in a long-distance relationship.”
- “The translation has high fidelity to the author’s style.”
- “Engineers improved the fidelity of the climate model.”
- “The insurer issued a fidelity bond to protect against employee theft.”
Sample sentences
- “Fidelity to the facts matters more than speed.”
- “They value emotional as well as sexual fidelity.”
- “This speaker delivers high-fidelity sound.”
- “The museum demanded fidelity to the original colors.”
- “He questioned the report’s fidelity in quoting sources.”
- “Couples should define what fidelity means for them.”
- “A low-fidelity prototype is faster to test.”
- “The oath requires fidelity to the constitution.”
- “The study measured the fidelity of program implementation.”
- “Her fidelity to the team never wavered.”
Synonyms
faithfulness, loyalty, allegiance, devotion, constancy, steadfastness, accuracy, exactness, verisimilitude, faith
Antonyms
infidelity, unfaithfulness, disloyalty, treachery, betrayal, inaccuracy, distortion
Related terms
faithful, faithfulness, loyal, loyalty, integrity, accuracy, precision, veracity, authenticity, monogamy, exclusivity, commitment, vow, infidelity, hi-fi, lo-fi, fidelity bond
Connection to sexuality
Fidelity is not itself a sexual term, but in relationships it often refers to honoring agreed boundaries about intimacy—sexual and/or emotional. In consensually non-monogamous settings, fidelity means keeping the specific agreements partners set.
Sexopedia.co is an educational glossary of sexual and gender-related terms—helping you improve your English while deepening your understanding of identity, language, and self-expression.