My definition is based on the pure and plain text of the Constitution. What is yours based on?
Reality. If they are not supposed to be here because their visa expired, they're here illegally. If by some pro-illegal action by our wonderful politicians they've conveniently wrote the law that that is not the case, then all the more shame upon us as citizens for not tossing their asses out sooner and putting in place people who represent the US, not illegals + some small subset of the US that is pro-illegal. Making excuses for it will not fix the problem.