unfasten to open the two sides of a piece of clothing, bag, belt etc:
It was hot in the waiting-room, so I unfastened my coat. Please do not unfasten your seatbelt while the vehicle is in motion.undo to unfasten clothes or unfasten buttons, zips etc on clothes:
My fingers were so cold that I couldn’t undo the buttons.untie to unfasten the knot that fastens shoes, a tie, a scarf etc:
He untied his shoes and kicked them off.unbutton to unfasten the buttons on a piece of clothing:
She slowly unbuttoned her blouse.unzip to unfasten clothes, bags etc by unfastening a zip:
She unzipped the case and took out a thick file.loosen to unfasten clothes a little, but not completely, in order to make yourself more comfortable:
Carter took off his jacket and loosened his tie.open to unfasten a bag, box, or other container:
‘Could you open your bag, please?’ said the security guard. [TahlilGaran] English Thesaurus ▲