Freebooting is certainly more specific than piracy, but I think you may have missed the word "like" in there. GP means that the word "freebooting" itself is not

Freebooting is certainly more specific than piracy, but I think you may have missed the word "like" in there. GP means that the word "freebooting" itself is not new, but its new meaning in today's context is (like "pirate") new.