My client has canceled a glossary, can we play back the file from a moodle-backup? Where the glossary is stored?
By "cancelled" I suppose you mean deleted? If you have a back-up of the Moodle course where that glossary instance had been created, then you can restore that deleted glossary the same was as you restore any other Moodle activity.
Which version of Moodle are you using?
Joseph