Wiktionary
unfastenable
a. 1 Not fastenable 2 Able to be unfastened.
Usage examples of "unfastenable".
The trussed Englishman departed for Argostoli at dawn, the turn-ups of his trousers half way up his pink calves and the jacket unfastenable, bearing his equipment in a hessian sack, also provided by the doctor, who would not let him depart without imparting some sound advice: `Look, OK?