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Synonyms

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

Other Word Forms

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

I walk over and begin to unfasten the row of tiny buttons along the back, slipping it over her head once it’s loose enough.

From "Dread Nation" by Justina Ireland

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

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

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

From Time Magazine Archive

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

From "Dreaming in Cuban" by Cristina García

I give it a press and the clasp unfastens.

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

But the giant birds will be unfastened from the ceiling on Friday to make way for a new mystery exhibit, airport authorities said.

From BBC May 5, 2025

The maintainers next unfastened the warhead from the missile and placed it in a specialized truck.

From Seattle Times Sep. 19, 2023

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

From Slate Aug. 2, 2022

At the end of the transect, Riis stopped at another parlous roadside spot, unfastened the net and removed the small bag at its tip.

From New York Times Nov. 27, 2018

Ned went to the window and unfastened the heavy shutters to let in the cool night air.

From "A Game of Thrones" by George R.R. Martin

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

“Help me! I am here,” Mr. Capello replied, unfastening his seatbelt, and climbing over the seats, through the smashed rear window.

From New York Times Sep. 6, 2018

People were unfastening my bindings and collecting my ski poles from where they poked skyward, askew, in their separate snowbanks.

From "The Bell Jar" by Sylvia Plath

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