unfasten

US /ʌnˈfæs.sən/
UK /ʌnˈfæs.sən/
"unfasten" picture
1.

undo or open the fastening of (something)

:
•
She reached up to unfasten the top button of her dress.
•
Please unfasten your seatbelt before leaving the aircraft.
:
unclaspunbuckleundounlatchunhook
:
fastensecureattach