FASTNESS Synonyms: 108 Similar and Opposite Words

fastness

noun

ˈfas(t)-nəs

Definition of fastness

as in speed

a high rate of movement or performance the amazing fastness with which the boy took his shower had us wondering if he'd used any water

Synonyms & Similar Words

Relevance

Antonyms & Near Antonyms

as in stronghold

a structure or place from which one can resist attack the guerillas retreated to their network of hidden fastnesses deep within the mountains

Synonyms & Similar Words

as in loyalty

adherence to something to which one is bound by a pledge or duty his uncompromising fastness to the cause of freedom was beyond question

Synonyms & Similar Words

Antonyms & Near Antonyms

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

Recent Examples of fastness The redyed fabrics showed uniform color uptake and washing and rubbing fastness comparable to the reference fabric, according to the study. — Alexandra Harrell, Footwear News, 26 Aug. 2026 Editors and contributors compare dozens of sets and look for qualities such as softness, durability, breathability, color fastness, and how well the linens launder and withstand wear. — Yelena Moroz Alpert, Architectural Digest, 20 Jan. 2026 Li said the color builds the familiar ring-dye, white-core look designers expect, then fades predictably in laundry while maintaining high light fastness (Grade 4–5) and strong anti-yellowing. — Angela Velasquez, Sourcing Journal, 11 Nov. 2025 Like the pressing, the hard work mentality and fastness of transition for example. — Andy Jones, New York Times, 29 May 2025 The Neutral Ground had cowboys (or Cow Boys), Indians, cavalry attacks and rescues, and secret woodland fastnesses known only to the canniest frontiersman. — Ian Frazier, The New Yorker, 15 July 2024

Recent Examples of Synonyms for fastness

Noun

On a circular track, place a group of runners, all of whom run at unique, constant speeds.

— Lyndie Chiou, Scientific American, 2 Oct. 2026
Layoffs are low but caution is high Layoff activity hasn’t picked up speed, according to the Labor Department’s weekly reports on unemployment insurance filings.

— Alicia Wallace, CNN Money, 1 Oct. 2026

Definition of speed

Noun

Pulled into the action is Liz Gold, an idealistic young woman whose courage and conviction force Leamas to navigate a world where loyalties fracture and betrayal is inevitable.

— Max Goldbart, Deadline, 28 Sep. 2026
Pulled into the action is Liz Gold (O’Casey), an idealistic young woman whose courage and conviction force Leamas to navigate a world where loyalties fracture and betrayal is inevitable.

— Alex Ritman, Variety, 28 Sep. 2026

Definition of loyalty

Noun

Preliminary flight data show the plane descended 17,400 feet over 92 seconds while reaching a peak velocity close to the speed of sound.

— Christine Valora, The Washington Examiner, 3 Oct. 2026
As global markets demanded higher performance thresholds, Gaydon answered with the ferocious Aston Martin DBX707, a high-velocity machine with premium luxury credentials plus supercar-slaying straight-line velocity.

— New Atlas, New Atlas, 2 Oct. 2026

Definition of velocity

Noun

The structures include monasteries and fortresses that showcase the reign of the Lombards, who played a major role in the development of medieval European Christianity.

— Evie Carrick, Travel + Leisure, 28 Sep. 2026
The legacy data center strategy relied on secrecy—unmarked, fortress-like facilities hidden behind high security fences with minimal community outreach.

— Kevin Brown, Forbes.com, 24 Sep. 2026

Definition of fortress

Noun

There could be work drama or commotion among your colleagues that shakes up existing allegiances, which will compel you to reevaluate who’s really on your team.

— Steph Koyfman, Condé Nast Traveler, 28 Sep. 2026
In that same scene, Adam also jokingly calls Olive a rebel, which could be a nod to Rey’s allegiance to the Resistance.

— Tanya Fedak, Variety, 26 Sep. 2026

Definition of allegiance

Noun

But now, San Bernardino, Riverside and Kern counties — once considered bastions of affordability — are all right there with them.

— Jack Flemming, Los Angeles Times, 25 Sep. 2026
The rise of far-right populism in Europe’s biggest economy, which has for decades been viewed as a bastion of stability, centrist policymaking and EU leadership, is being closely watched across the continent.

— Jenni Reid, CNBC, 21 Sep. 2026

Definition of bastion

Noun

There’s an Islamic hadith in which the Messenger of Allah is asked by a man to name the person most deserving of his love, attention, and dedication.

— David Fear, Rolling Stone, 28 Sep. 2026
Carrie Coon will be the first recipient of the Vancouver International Film Festival’s new Luminary Award in the acting category, honoring excellence and dedication to the art of moving image.

— Katherine Brodsky, Variety, 28 Sep. 2026

Definition of dedication

Browse Nearby Words

fasting

fastness

fasts

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Style

“Fastness.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/fastness. Accessed 4 Oct. 2026.

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Synonyms of fastness

noun

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