Meritorious defense refers to a defense that addresses the substance or essentials of a case rather than technical objections or delaying tactics. It can be a defense that is based on evidence sufficient to warrant setting aside a default judgment against the defendant in civil litigation. It can also refer to a defense that appears likely to succeed or has already succeeded.
For example, in Michigan in a medical malpractice suit the defendant is required to include an affidavit of meritorious defense when filing the answer to the complaint of medical mal practice.[MCLS § 600.2912e]. This measure was adopted to decrease the number of frivolous malpractice suits filed against doctors and hospitals.