1. the property (of a problem or difficulty) that makes it impossible to solve • Syn: unsolvability • Ant: solubility, solvability (for: unsolvability) • Derivationally related forms: insoluble • Hypernyms: property 2. the quality of being insoluble and difficult to dissolve in liquid • Ant: solubility • Derivationally related forms: insoluble • Hypernyms: quality