1. Cause to become undone
   "unfasten your belt" 
2. Become undone or untied
   "The shoelaces unfastened"

Derived forms: unfastened, unfastens, unfastening

See also: unfastener, unfastening

Type of: open, open up, undo

Antonym: fasten

• defaulter
• defeasance
• defeasible
• defeat
• defeated
• defeatism
• defeatist
• defecate
• defecation
• defecation reflex
• defecator
• defect
• defect of speech
• defection
• defectionist
• defective
• defective pleading
• defectively
• defectiveness
• defector
• defeminise
• defeminize
• defence
• defence attorney
• defence contractor