Definitions for "Unopened"
Keywords:  untrimmed, knife, unread, folds, joined
The pages of the book are still joined at the folds and uncut.
The edge folds of the signatures unsevered. Many books in the last century were so issued; the reader was expected to have the binder do the job or to open the pages with a paper-knife.
The leaves of the book have been folded but not cut, making it impossible to flip single pages for reading, without first cutting the folds to make individual sheets. See
To present participles which come from intransitive verbs, or are themselves employed as adjectives, to mark the absence of the activity, disposition, or condition implied by the participle;
not yet opened or unsealed; "unopened Christmas presents"