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Re:Ask HN: Competitor is successful with black hat SEO by angry-hacker on Monday March 20, 2017 @09:14AM (#13913850)
Theoretically yes: https://www.google.com/webmasters/tools/spamreport?hl=en

No idea if it has any impact.

Re:Ask HN: Competitor is successful with black hat SEO by koolba on Monday March 20, 2017 @09:23AM (#13913929)
I bet part of the black hat SEO toolkit involves a distributed reporting of your competitors as spam using this exact link.