Definition of unfasten in US English:



[with object]
  • 1Open the fastening of; undo (something)

    ‘Allie stands before the mirror unfastening her earrings’
    ‘he had left the door unfastened’
    • ‘Allsop unfastened the chain and threw the door open.’
    • ‘She nodded and unfastened her seat belt as Wil came around to open the door for her.’
    • ‘He closed the door again and unfastened the chains, opening the door again, all the way this time.’
    • ‘She shakily unfastened her seat belt and opened the car door.’
    • ‘Without a word he reached to his side and untied another tarp bag, unfastening it but leaving it unopened on the desk in front of him.’
    • ‘I slowly removed my earphones, secured my book, and unfastened my seatbelt.’
    • ‘Lincoln tapped her feet and rubbed a handful of nibbled fingernails up and down her jacket as if fastening and unfastening a zip.’
    • ‘It unfastened my uniform top and tugged it open.’
    • ‘Vincent ignored her, unfastening his seatbelt and opening his door.’
    • ‘Jack unfastened the lock and shoved the door open, much to Vaun's horror.’
    • ‘I heard the door lock being unfastened and the door opened.’
    • ‘Steve could heard the sound of many, many locks being unfastened, then the door opened a crack.’
    • ‘I hit the door hard, unfastening my seat belt and reaching for the handle behind me.’
    • ‘With a silent sigh to himself, he unfastened the helmet and removed it altogether.’
    • ‘He dropped his cap on a chair, unbuttoned his overcoat, lifting up his chin to unfasten the throat buttons.’
    • ‘I unfastened my belt buckle and unbuttoned my camouflage pants.’
    • ‘Jenna unfastened the lock on her makeup case and flipped it open.’
    • ‘Walker sat up, unfastened his strap, and opened his door.’
    • ‘Satisfied that I was safe for the time being I tried to unfasten the door again.’
    • ‘Keeping his eyes on the open glade, he carefully unfastened the packsack and slipped out the revolver.’
    undo, open, detach, disconnect, remove, untie, unbutton, unzip, loose, loosen, free, separate, disengage, disjoin, uncouple, unwrap, unbind, unhook, unlace, unhitch, untether, unlock, unbolt
    View synonyms
    1. 1.1no object Become loose or undone.
      • ‘If the patch unfastens, it becomes a loose body in the knee and requires surgical removal.’
      • ‘The band unfastened with a snap and a pop, then blood flowed back into her arm.’
      • ‘Because the fabric's material fastens and unfastens so easily, Ray can move the bands any time they look like they need repositioning.’