It means that page is a dead end for search spiders. “no index” means “don’t place this page in the Google (or Bing) index, and/or remove it if it is already indexed”. “no follow” means “don’t crawl through and visit any of the links on the page”.
Generally there are good reasons to “noindex” a page, but most of the time you want the spiders to crawl through (and the SEO page rank to pass through as well), so “no follow” should be used sparingly.