Thesaurus Dictionary
Synonyms and antonyms of To unfasten, or to come unfastened in American Thesaurus
To unfasten, or to come unfastened
to become undone/untiedetc.
detachable (adjective)
a detachable part can be removed and put back on again
unbuckle (verb)
to remove something that fastens with a buckle, especially a seat belt