coinsurerglossary / COINSURER coinsurer. An insurer who shares losses sustained under an insurance policy. See coinsurance under INSURANCE. [Cases: Insurance 2285. C.J.S. Insurance §§ 1137–1143.] 词条贡献者 法律翻译徐玲,知名法学院保险法专业,专注翻译各类与保险追偿有关的法律文件。