1
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
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Antonyms & Near Antonyms
2
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
3
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
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Antonyms & Near Antonyms
Example Sentences
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Recent Examples of fastness
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
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
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In a field experiment with hundreds of consultants, GPT-4 improved speed and quality on some knowledge tasks while performance dropped on other, seemingly similar tasks just outside its strengths.—
Arkansas Online,
Arkansas Online,
8 Jan. 2026
-
Tapascott said speed alone no longer excites drivers.—
Aamir Khollam,
Interesting Engineering,
8 Jan. 2026
Noun
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McDonald said DeSantis also could be trying to shore up Republican strongholds to mitigate the losses generally experienced by the party in power during midterm elections.—
Mike Schneider,
Los Angeles Times,
8 Jan. 2026
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Campbell’s main support always came from the union stronghold of Pueblo, in southern Colorado.—
Dave Marston,
Denver Post,
6 Jan. 2026
Noun
-
Kim Jee-woon’s A Bittersweet Life (2005) drew on the cool aesthetics of Jean-Pierre Melville’s gangster films while examining specifically Korean concepts of loyalty and social hierarchy.—
Literary Hub,
Literary Hub,
29 Jan. 2026
-
Just like the zodiac, every Bridgerton character embodies a distinct persona, from bold passion and quiet devotion to intellectual chemistry and soul-level loyalty.—
Valerie Mesa,
PEOPLE,
28 Jan. 2026
Noun
-
In fact, the computer science major has worked in the high-velocity world of consulting since 2006.—
Brock Keeling,
Oc Register,
27 Jan. 2026
-
Impressively, the researchers found that minute, transient voltage fluctuations in these segments encode precise velocity data.—
Chris Young,
Interesting Engineering,
26 Jan. 2026
Noun
-
Royal Isabela resembles a fortress, especially from a distance.—
Condé Nast,
Condé Nast Traveler,
22 Jan. 2026
-
This is the task of the middle powers, the countries that have the most to lose from a world of fortresses and most to gain from genuine cooperation.—
Haley Ott,
CBS News,
21 Jan. 2026
Noun
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In their proposals, city leaders ask DART to refund sales tax, change services, reform the agency’s governance model — a move Dallas leaders are considering — and increase transparency in exchange for calling elections off or recommending allegiance to DART.—
Lilly Kersh,
Dallas Morning News,
24 Jan. 2026
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Different ideas were discussed, including sending everyone in Greenland a check as a way to buy their allegiance.—
Jonathan Lemire,
The Atlantic,
23 Jan. 2026
Noun
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The city was once a bastion of boutique hotels—such as the forthcoming El Cortés, opening in Roma Norte in March in a 1915 Art Nouveau mansion—but the scene is shifting as the big names arrive.—
CNT Editors,
Condé Nast Traveler,
22 Jan. 2026
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Wikipedia is one of the last bastions of the early internet, but that original vision of a free online space has been clouded by the dominance of Big Tech platforms and the rise of generative AI chatbots trained on content scraped from the web.—
Arkansas Online,
Arkansas Online,
18 Jan. 2026
Noun
-
Fortunately, Rushdie’s beloved wife, fellow writer and multidisciplinary artist Rachel Eliza Griffiths, was on hand with a fierce dedication and a new camera.—
Kate Erbland,
IndieWire,
26 Jan. 2026
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Harp said Keane’s dedication to her role was unmatched.—
Keith M. Phaneuf,
Hartford Courant,
26 Jan. 2026
Cite this Entry
“Fastness.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/fastness. Accessed 30 Jan. 2026.
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