Antonyms of verb fasten

2 of 4 senses of fasten

Sense 1
fasten, fix, secure -- (cause to be firmly attached; "fasten the lock onto the door"; "she fixed her gaze on the man")
       Antonym of unfasten (Sense 1)
      => unfasten -- (cause to become undone; "unfasten your belt")

Sense 2
fasten -- (become fixed or fastened; "This dress fastens in the back")
       Antonym of unfasten (Sense 2)
      => unfasten -- (become undone or untied; "The shoelaces unfastened")

Synonyms/Hypernyms (Ordered by Estimated Frequency) of verb fasten

4 senses of fasten

Sense 1
fasten, fix, secure -- (cause to be firmly attached; "fasten the lock onto the door"; "she fixed her gaze on the man")
       => attach -- (cause to be attached)

Sense 2
fasten -- (become fixed or fastened; "This dress fastens in the back")
       => attach -- (become attached; "The spider's thread attached to the window sill")

Sense 3
fasten -- (attach to; "They fastened various nicknames to each other")
       => attach -- (cause to be attached)

Sense 4
tighten, fasten -- (make tight or tighter; "Tighten the wire")
       => change, alter, modify -- (cause to change; make different; cause a transformation; "The advent of the automobile may have altered the growth pattern of the city"; "The discussion has changed my thinking about the issue")