Would calling someone a "crook" even qualify as defamation? That's an opinion I can have about my local grocer because he charges slightly more for a half gallon of milk than Trader Joes does for a gallon. It's still an opinion regardless whether I'm wrong about the price of milk (I haven't checked but according to my buddy who worked at TJs it's a loss leader, so I'm going to recklessly assume the grocer is a crook).
In the US, it would only count as defamation if it were stated as a fact and was untrue, and any reasonable person given the same information would have suspected that it might not be true.
If it's true, there is no defamation. If it was stated as opinion, there is no defamation.
