What is the fair comment defence to a defamation claim in Ontario?

Fair comment protects genuine expressions of opinion, rather than statements of fact, made on a matter of public interest, provided the opinion is recognizably an opinion, is based on facts that are true or otherwise protected, and could honestly be held by someone looking at the known facts, even if most people would strongly disagree with the view expressed. The defence exists to protect robust debate and criticism, about businesses, public figures, artistic work, and similar subjects, without requiring the commentator to prove their opinion is correct, only that it is a genuinely held view grounded in accurate underlying facts rather than fabricated ones.

This defence can be defeated if the plaintiff shows the comment was made with malice, meaning it was not really a genuine opinion at all, but was made for an improper purpose, such as knowingly spreading falsehoods dressed up as opinion to cause harm. The key practical challenge in these cases is often distinguishing a genuine opinion, however harsh, from an implied factual assertion that is simply disguised as one.