Nofollow: Nofollow (or "no follow") is an attribute given to links in order to prevent them from passing link authority. In other words, if a webmaster doesn't want to use low-quality links to direct users to his or her website, he or she would specify nofollow when placing a link on another site.
Nofollow links are commonly used within user-generated content on other sites, such as in the comments section of a blog. Here a webmaster may want to promote his or her own website, but he or she wouldn't want to have that link be indexed by search engines. Having to many follow links in user-generated content can appear spammy in some cases and can reduce a website's rank rather than enhance it.
In order to specify which links are nofollow links, all users have to do is add information to a typical HTML link, like this (but without the additional spaces):
< a href="https://www.example.com" rel="nofollow" > link text < /a >
Nofollow can also be added into a site's meta data to prevent search engines from counting the outbound links on a page: < META NAME="ROBOTS" CONTENT="INDEX, NOFOLLOW" >