medigap insuranceglossary / medigap insurance medigap insurance. Slang. A private insurance policy for Medicare patients to cover the costs not covered by Medicare. Cf. MEDICARE. 词条贡献者 译者张文,国际知名商学院金融专业,擅长翻译各种与结构性融资及衍生品诉讼相关的法律文件。