What fallacy is it when an argument attacks the person rather than the person's beliefs?

That kind of fallacy is called Argumentum ad Hominem. It means the argument is addressed to the person; attacking that person instead the issue. There is an irrelevance because the argument is against to the person making a claim, rather against to the claim itself. An example is judging a person's social status or attitude, like calling his strategies aren't effective to finish a certain task because of his untidiness and laziness.