[ uhn-fas-uh n, -fah-suh n ]
/ ʌnˈfæs ən, -ˈfɑ sən /

verb (used with object)

to release from or as from fastenings; detach.
to undo or open (something fastened).

verb (used without object)

to become unfastened.

Origin of unfasten

First recorded in 1175–1225, unfasten is from the Middle English word unfastnen. See un-2, fasten
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Examples from the Web for unfasten

British Dictionary definitions for unfasten

/ (ʌnˈfɑːsən) /


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