You can delete a bucket and recreate another bucket with the same name. Be aware that the new bucket is a different bucket (a different ID) that happens to have the same name.
After you delete a bucket, all objects in that bucket are inaccessible, even if you subsequently create another bucket with the same name.
Best practice
For best results, wait at least twice the value of the cache.realmStaleTimeout parameter before you recreate a bucket with the same name as a bucket you just deleted.
If the cache.realmStaleTimeout is still at the default value of 10 minutes (600 seconds), delete the bucket, wait 20 minutes, and then create the new bucket.