What nofollow means
The nofollow value in a link’s rel attribute qualifies the relationship between the linking page and the destination. Google treats qualifying link attributes as hints when deciding how to understand and use links; nofollow is not a simple guarantee about the movement of a fixed amount of PageRank.
Google also supports sponsored for advertisements or paid placements and ugc for user-generated links. Use the relationship that accurately describes the link rather than attach attributes solely to manipulate a score.
Nofollow is different from noindex
A nofollow link does not prevent the destination from being indexed. Search engines may discover the same URL through other links or sources. A noindex instruction on a page has a different purpose, and the crawler needs access to read it.
Our noindex checker examines the directives returned by a public URL. It does not establish how Google has used a backlink or whether the destination is currently indexed.
Review the actual link
Check the rendered anchor, its rel values and the commercial or editorial relationship. Avoid absolute claims that one attribute makes every link worthless or ensures a ranking benefit.
Sources
Google: qualify outbound links and Google’s explanation of link-attribute hints.