What is the definition of a frivolous claim?

This lack of definition presents a problem both for attorneys and for the administration of justice. Counsel face the danger of being trapped between their obligation to their clients to diligently pursue any possibly meritorious claim, and their obligation to the judicial system to refrain from prosecuting frivolous claims. "[A]n attorney is often confronted with clashing obligations imposed by our system of justice. An attorney has an obligation not only to protect his client's interests but also to respect the legitimate interests of fellow members of the bar, the judiciary, and the administration of justice." (Kirsch v. Duryea (1978) 21 Cal.3d 303, 309, 146 Cal.Rptr. 218, 578 P.2d 935.)