You can disable your repository's wiki.
Wikis are available in public repositories with GitHub Free, and in public and private repositories with GitHub Pro, GitHub Team, GitHub Enterprise Cloud, and GitHub Enterprise Server. For more information, see "GitHub's products."
When you turn off a wiki, the content is hidden, but not erased. If you choose to re-enable wikis later, your previous pages will be restored.
On GitHub, navigate to the main page of the repository.
Under your repository name, click Settings.
Under Features, unselect Wiki.