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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This time, the study included a vocabulary of over 1,000 words and achieved a median speed of 78 words per minute.—
Rob Toews,
Forbes.com,
22 June 2026
-
Weah acknowledged Mbappe’s speed and performance after his brace helped France to a 2-1 win.—
Ben Church,
CNN Money,
21 June 2026
Noun
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As a result, Democrats make inroads even on longtime local Republican strongholds.—
Matthew Blinstrubas,
Hartford Courant,
21 June 2026
-
Morales has been entrenched in his coca-growing stronghold in the Chapare region since 2024 and has refused to appear before the courts.—
ABC News,
ABC News,
21 June 2026
Noun
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In India, Shilangi Mukherji, director and head of SVOD Business at Prime Video India, said audience loyalty has been driven by a combination of local originals, licensed programming and long-term investment in intellectual property.—
Lin Ying-Hsuan,
Variety,
17 June 2026
-
That sense of loyalty became a feedback loop.—
Gustavo Turner,
HollywoodReporter,
17 June 2026
Noun
-
Cabrera’s velocity cratered in the fifth, especially on his changeup, which lost 3 mph from the first inning.—
Meghan Montemurro,
Chicago Tribune,
17 June 2026
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Lane is throwing his fastball in the low 90s, with upside to add velocity as the summer goes along, with a put-away slider.—
Dom Amore,
Hartford Courant,
15 June 2026
Noun
-
Written and produced by Australian filmmaker Anthony Maley, the project follows three unlikely insect heroes who infiltrate a vast human chemical fortress in search of an antidote to a toxin threatening the survival of their world.—
Andreas Wiseman,
Deadline,
17 June 2026
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After previous coaches played home matches away from the timeless and intimidating Defensores del Chaco national stadium in Asunción, Alfaro restored that hallowed ground as Paraguay’s footballing fortress.—
Felipe Cardenas,
New York Times,
10 June 2026
Noun
-
The kingdom and its press and thus the world could see the war hero and his monarch inextricably bound by allegiance to Britain.—
Guy Martin,
Forbes.com,
19 June 2026
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Many with mixed backgrounds switched allegiances when turning senior, following their heart – or their ambition.—
ABC News,
ABC News,
19 June 2026
Noun
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In it, Rocío, played by Rocío Molina, a leading light of the international flamenco vanguard, returns to her Ebro Delta home to attend the funeral of her mother, a bastion of traditional flamenco.—
John Hopewell,
Variety,
18 June 2026
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Bored Lord and AceMo, longtime bastions of their respective coastal scenes, offer up two rumbling club heaters.—
Benny Sun,
Pitchfork,
17 June 2026
Noun
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The party highlighted his lifelong dedication to the independence movement and his role in promoting national unity, dialogue, peace and political stability throughout his public career.—
ABC News,
ABC News,
22 June 2026
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The spectators, meanwhile, were a perfect mix of first-timers and lifers, with both groups taking their dedication to the theme very, very seriously.—
Amir Hamja,
Vogue,
22 June 2026
Cite this Entry
“Fastness.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/fastness. Accessed 25 Jun. 2026.
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