A link relationship value used to qualify a link when you do not want to endorse or associate with its destination.
A practical example
An untrusted external reference can use rel=nofollow; paid placements should normally use rel=sponsored.
What to watch for
Google treats link qualifications as hints. Nofollow is not a reliable way to prevent a destination page being crawled or indexed.
Related reading
Explore Backlink and robots.txt. Try our noindex checker for a practical next step. See how this fits into Technical SEO.