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
Relevance
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
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
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
-
Beat in butter using an electric mixer on medium speed until creamy, about 2 to 3 minutes.—
Sarah Martens,
Better Homes & Gardens,
14 June 2026
-
Investigators said Garcia Aguilar fled, prompting deputies to terminate the pursuit because of the high speeds involved.—
Zachary Bynum,
CBS News,
14 June 2026
Noun
-
The district includes portions of Miami-Dade and Broward counties and has long been considered a Democratic stronghold.—
Jim DeFede,
CBS News,
14 June 2026
-
Funeral ceremonies are expected to begin in Tehran and move to Qom, a stronghold of many senior Shiite clerics, then to Mashhad, Khamenei's birthplace.—
Arkansas Online,
Arkansas Online,
14 June 2026
Noun
-
His politics are rooted in loyalty, grievance, retaliation, and the constant testing of institutional limits.—
Paul Oestreicher,
Hartford Courant,
10 June 2026
-
Some leaders earn the type of loyalty that guarantees them allies even as their fortunes fall, while leaders who rely on intimidation are the first to find themselves alone once their influence diminishes.—
Colin Pascal,
Baltimore Sun,
10 June 2026
Noun
-
If there’s any big bugaboo in his profile, he can be beaten by higher-end velocity, but his ability to adjust to secondary offerings keeps him afloat.—
Gary Bedore,
Kansas City Star,
10 June 2026
-
Tiny silica beads about 10 microns in diameter are projected at the polymer at about 750 meters per second (over 1,600 miles per hour) with the amount of energy absorbed measured by calculating the change in particle velocity before and after the beads pass through.—
Shirl Leigh
June 10,
New Atlas,
10 June 2026
Noun
-
Today, visitors can explore the fortress, spread out for a picnic on the green lawn and take in sweeping views of America’s Oldest City from the gun deck.—
USA TODAY Network,
USA Today,
10 June 2026
-
Perhaps the best way to understand Helsinki’s origins is to take the short ferry ride across the harbor to the island-fortress of Suomenlinna (now a popular park).—
Tribune News Service,
Baltimore Sun,
10 June 2026
Noun
-
Sports is a tricky format to play with in these times of shifting media allegiances.—
Brian Steinberg,
Variety,
21 Aug. 2025
-
Jones said both Wei and his mother were anti-communist and held no allegiance to China.—
Alex Riggins,
San Diego Union-Tribune,
20 Aug. 2025
Noun
-
For instance, the conservative rural North State would be denied any real representation as the district would swoop down to take in Marin County, the liberal bastion just north of the Golden Gate Bridge.—
The Editorial Board,
Oc Register,
19 Aug. 2025
-
The bastion, the fortifications, the views all shape the mood for diners.—
Liza B. Zimmerman,
Forbes.com,
19 Aug. 2025
Noun
-
As my eyes processed that large blue plus sign, a new version of love and dedication exploded through my chest.—
Jayme Serbell,
Vogue,
15 June 2026
-
Their dedication did not just solve a cold case.—
DeJanay Booth-Singleton,
CBS News,
15 June 2026
Cite this Entry
“Fastness.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/fastness. Accessed 18 Jun. 2026.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
