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
-
In reality, many ballistic missiles already reach hypersonic speeds at certain points in their flight.—
Kaif Shaikh,
Interesting Engineering,
31 May 2026
-
Carriers often became obsessed with speed and efficiency.—
Peter Hessler,
New Yorker,
31 May 2026
Noun
-
Iowa voters head to the polls Tuesday for primary elections that have become one of Democrats’ key focuses in their bid to claw back power in a state that once helped launch former President Barack Obama to the White House but has since become a Republican stronghold.—
Claire Carter,
The Washington Examiner,
31 May 2026
-
This remarkably intact 19th-century stronghold saw use during the Civil War and the Spanish-American War.—
Taryn Shorr-Mckee,
Travel + Leisure,
31 May 2026
Noun
-
The introduction of Diamond Reserve reaffirms Hilton Honors’ commitment to recognizing loyalty at every level, elevating the experience for its most frequent guests through a more refined and intentional approach.—
Robb Report Studio,
Robb Report,
4 June 2026
-
Plus, Fan Club loyalty members enjoy a free donut of their choice.—
Laura Daily,
Denver Post,
3 June 2026
Noun
-
His career with the Giants had been a mixed bag due in part to a shoulder ailment that hampered his rookie season, but there was clear upside if Harrison could regain his velocity.—
Justice delos Santos,
Mercury News,
3 June 2026
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On the opposite side, the spin works against airflow, causing a decrease in air velocity.—
Encyclopedia Britannica,
Encyclopedia Britannica,
3 June 2026
Noun
-
Surviving the onslaught would require no less than a flying fortress with complex magnetic shielding.—
Kai James,
The Conversation,
26 May 2026
-
The trailers show that Eternia was once a vibrant alien-like world with multi-colored forests, massive mountains and fortresses with towering faces carved into their entrances.—
Caroline Reid,
Forbes.com,
25 May 2026
Noun
-
Hudson Williams, the Canadian sweetheart behind the smash hit Heated Rivalry, has pledged his allegiance to the English department.—
Brittany Allen,
Literary Hub,
29 May 2026
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Aliji previously pleaded guilty on April 28, admitting to the charges after prosecutors accused him of pledging allegiance to the Islamic State and planning an assault targeting fans gathered outside Ernst Happel Stadium during Swift’s August 2024 concerts.—
Bryan West,
USA Today,
28 May 2026
Noun
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This family home was a bastion of social and political life for many years before it was abandoned in the second World War, eventually becoming a shelter for those displaced.—
Katie Silcox,
Vogue,
28 May 2026
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Like Heated Rivalry before it, Off Campus presents the stereotypically male sport not as a bastion of aggressive masculinity, but as a space for community and care.—
Anna Rinderspacher,
Glamour,
20 May 2026
Noun
-
But that continued dedication to masking of any kind is not merely the result of unintelligence, or misplaced hypochondria, or even being affiliated with a specific political party.—
Ian Miller OutKick,
FOXNews.com,
1 June 2026
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He is remembered for his generosity to families in need, and his dedication to giving back to his community.—
Shardaa Gray,
CBS News,
1 June 2026
Cite this Entry
“Fastness.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/fastness. Accessed 4 Jun. 2026.
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