A reviewer is someone who examines something carefully and shares their informed opinion about it. When a book reviewer reads a new novel, they don't just say whether they liked it: they explain what works, what doesn't, and why. Movie reviewers watch films and help audiences decide what's worth seeing. Product reviewers test new gadgets and describe how well they actually perform.

Good reviewers know a lot about what they're reviewing. A video game reviewer has played hundreds of games and understands what makes them fun or frustrating. A restaurant reviewer knows about cooking techniques and flavor combinations. Their experience helps them spot things casual observers might miss.

Reviews differ from simple opinions because they include reasoning and evidence. If you tell your friend “that movie was boring,” that's an opinion. If you explain that the plot moved too slowly and the characters weren't believable, you're thinking like a reviewer. Teachers act as reviewers when they read your essays and explain what's strong and what needs improvement.

The word can also mean someone who reviews material to check it, like a peer reviewer in science who examines another researcher's work before it gets published, or an editor who reviews articles for mistakes.