Usually one of four. In our read, a review an owner calls fake lands under Fake Engagement, Off-topic, the conflict-of-interest clause under Rating Manipulation, or Impersonation. Which one depends on what the review says and who could have written it. You can work it out by hand below, or run the free analysis on your reviews and see which ones have grounds for removal.
Fake Engagement is the one for a review with no real experience behind it. Someone who never came in. Someone who was paid. One person posting from several accounts. Google's Fake Engagement section also names a competitor posting on your business to hurt it. The details and worked examples are on our page about fake engagement in Google reviews.
Off-topic covers a review that isn't about an experience at your business at all. If it clearly names some other business, another location, or a place you couldn't have served, that's the cleaner argument. A complaint about a service you don't offer isn't enough on its own. That's evidence, not grounds. Our page on off-topic Google reviews shows where the line sits.
Rating Manipulation holds the conflict-of-interest clause. It names current and former employment, family ties, and industry competitors outright. Google repeats the conflict-of-interest sentence under Misrepresentation, but without the examples of competitors and family.
Impersonation is the narrow one owners miss. It covers a review posted in a real person's name by someone who isn't that person. If a customer tells you they never wrote the review under their name, read about impersonation in Google reviews.
A one-star you'd call fake may not reach any of these. A real customer who had a bad day and wrote it up badly is still a real customer. That review stays up.