To de-index pages, upload a robots.txt file to the public_html.

The format is:

User-agent: *
Disallow: /

After the / list the permalink you want to de-index. For example, it you did want Google to crawl mywebsite.com/page1 or mywebsite.com/page2, the robots.txt file would be:

User-agent: *
Disallow: /page1
Disallow: /page2