noun
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
Useful english dictionary. 2012.