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unfasten

American  
[uhn-fas-uhn, -fah-suhn] / ʌnˈfæs ən, -ˈfɑ sən /

verb (used with object)

  • unfastens,
    present (3rd person singular)
  • unfastened,
    past participle,  past
  • unfastening
    present participle
  1. to release from or as from fastenings; detach.

  2. to undo or open (something fastened).


verb (used without object)

  • unfastens,
    present (3rd person singular)
  • unfastened,
    past participle,  past
  • unfastening
    present participle
  1. to become unfastened.

unfasten British  
/ ʌnˈfɑːsən /

verb

  1. to undo, untie, or open or become undone, untied, or opened

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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Inflected Forms

Participles

Conjugated Forms

Present

Past

Future


Etymology

Origin of unfasten

First recorded in 1175–1225, unfasten is from the Middle English word unfastnen. See un- 2, fasten


Explanation

When you unfasten something, you loosen or open it. You should wait to unfasten your seatbelt until the car has completely stopped. To fasten is to hook, close, or latch something, and to unfasten it is to undo it. You might unfasten your dog's leash so she can run free on the beach or unfasten the snaps and buttons on your jacket so you can take it off. You can also unfasten your ponytail, letting your hair down, or unfasten the latch on a gate. The Old English root word is fæstnian, "make fast or firm."

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Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

For 12 days, we shared every moment and, surrounded by the kind of beauty only a remote bay in the Pacific could afford, I felt something unfasten in my chest.

From Los Angeles Times ● Mar. 8, 2024

To serve the cheesecake, run a knife around the outer edge to loosen it from the pan, then carefully unfasten the sides of the pan and transfer the cheesecake to a cake plate or stand.

From Fox News ● Dec. 16, 2021

Operators are supposed to unfasten all of the seat belts after each ride so the next load of people can be buckled in.

From Seattle Times ● Sep. 25, 2021

Turn off the heat, allow the pressurized steam to escape, then unfasten the lid and check for doneness; you want your beans to be very tender and quite creamy.

From Washington Post ● Jun. 3, 2018

Katya had to unfasten her straps and climb up out of the cockpit to prove that she and her crew were ready for combat.

From "A Thousand Sisters" by Elizabeth Wein

The bearded guy in front of us unfastens his earflaps and says, chuckling, “Haven’t you guys ever stood in line for beer before?”

From Washington Post ● Sep. 6, 2017

Home for the busy man about Brazil these days is where he unfastens his seat belt.

From Time Magazine Archive

One Atlanta man unfastens his seat belt, and turns off his hearing aid, as soon as he starts his new Impala.

From Time Magazine Archive

I give it a press and the clasp unfastens.

From "Amari and the Night Brothers" by B.B. Alston

Then she unfastens the tiny clasp in her right ear and surrenders the other pearl.

From "Dreaming in Cuban" by Cristina García

"At first, I thought I was going to die. I managed to open my eyes, unfastened my seat belt and tried to exit the plane."

From BBC ● Jun. 13, 2025

An old friend used to call these neither-here-nor-there realms the “zero world” for the way they feel unfastened from reality, parallel to daily life but separate.

From New York Times ● May 11, 2024

Sempill and Dollfus, whose belts were unfastened, were flung out.

From Slate ● Aug. 2, 2022

Forensic investigations found two broken bolts and another that unfastened while the engine was running.

From Seattle Times ● Mar. 15, 2022

They have layers of tulle and are propped up underneath with crinolines, and I worry about the hooks coming unfastened.

From "Cat's Eye" by Margaret Atwood

Kondo brought garments to life, like kites in the sky with voluminous silhouettes created by fastening and unfastening buttons.

From Seattle Times ● Jun. 20, 2024

He must have disembarked in Cold Lake, where they had stopped so briefly that Vaughn hadn’t even bothered unfastening her seat belt.

From Slate ● Jul. 30, 2022

Fastidiously spend a couple of minutes unfastening all the straps before you can sit down?

From The Guardian ● Sep. 19, 2019

Sunday, officers can be seen breaking a front window, unlocking the door and unfastening the driver’s seat belt.

From Washington Post ● Feb. 21, 2017

“He needs me,” I said, finally unfastening the BiPAP myself.

From "The Fault in Our Stars" by John Green

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