Civil torts are illegal, even though they are not criminal.
> The law defines infringement but does not prohibit it, but merely provides mechanisms of civil remedy.
That is incorrect, the law prohibits torts like infringement as much it prohibits criminal offenses. (It may do so by simply specifying the consequence of violation of the prohibition without separately stating the prohibition independently, but this is typical of criminal laws as well -- which are often phrased as "whoever does <prohibited act> shall be punished with <punishment>", so if we accepted the prohibition/consequence distinction for torts, we'd have to do so for crimes as well, and say crimes are not "illegal".)
> Fair use is not infringement.
Sure, but that's a non-sequitur.
> You may be thinking of criminal copyright infringement.
No, I'm just not falsely limiting "illegal" to "criminal".