What's harm?

So we have laws- and most laws are to avoid harm to humans. But where does harm end? Should it just be subjected to physical harm? Or emotional harm? Laws being applied to harm being caused emotionally are dangerous; you can't physically see the harm or measure it. Therefore that harm is subjective; the person decides if it harms them. But can we trust that it emotionally harmed them just because they say so- and should whoever harmed them emotionally be punished even if that wasn't their intent?