A wiki administrator can delete the wiki. When you delete a wiki, all content in the wiki, blog, calendar, and mailing list is destroyed.
Warning: Deleting a wiki is permanent. Make sure you back up all critical data stored in the wiki before deleting it.
To delete a wiki:
While viewing My Page, click Wikis.
Hold the pointer over the link to the wiki and then click the Delete (X) link.
If the Delete (X) link doesn't appear, you don't have administrator access to the wiki and you can't delete it.
When prompted to confirm, click Delete.