What is considered "substantial merit" for a claim?

In Pointes Protection, “substantial merit” was defined as a real prospect of success. The requirement was further refined in Bent v. Platnick as demonstrating a prospect of success that need not be demonstrably likely, but one that weighs more in favour of the plaintiff.

Substantial merit has been described as a more demanding standard than that applicable on a motion to strike a claim pursuant to Rule 21 of the Rules of Civil Procedure for failure to disclose a cause of action. Accordingly, more than merely some chance of success is required. In Bent v. Platnick, was stated (at para. 49): …for an underlying proceeding to have “substantial merit”, it must have a real prospect of success — in other words, a prospect of success that, while not amounting to a demonstrated likelihood of success, tends to weigh more in favour of the plaintiff. In context with “grounds to believe”, this means that the motion judge needs to be satisfied that there is a basis in the record and the law — taking into account the stage of the proceeding — for drawing such a conclusion. This requires that the claim be legally tenable and supported by evidence that is reasonably capable of belief.