The old house is in such poor condition that it's considered uninsurable by insurance companies.

uninsurable 是由前缀 un-（表示"不、非"）和形容词 insurable（可投保的）组成的形容词。insurable 来自动词 insure（投保、保险），加上后缀 -able 表示"能够...的"。uninsurable 合起来表示"无法投保的、不具备投保条件的"。