Justiciability refers to the types of matters that a court can adjudicate. If a case is "nonjusticiable," then the court cannot hear it. Typically to be justiciable, the court must not be offering an advisory opinion, the plaintiff must have standing, and the issues must be ripe but neither moot nor violative of the political question doctrine. Typically, these issues are all up to the discretion of the court which is adjudicating the issue.
An advisory opinion is a court's nonbinding interpretation of a legal question.
Under Article III, Section 2 of the Constitution, a federal court may only adjudicate an actual controversy. This is referred to as the Case and Controversy Clause.
Some state courts are allowed to issue advisory opinions under limited circumstances, however these circumstances are typically enumerated within that state's constitution.
A claim is ripe when the facts of the case have matured into an actual controversy. A case is not ripe if the harm to the plaintiff has not yet occurred.
A claim is moot if the relevant issues have already been resolved.
Political Question Doctrine
Under the political question doctrine, a court will refuse to hear a case if the relevant issues are politically charged.