insolubleadjective · Level 3 SAT1(of a substance) incapable of being dissolvedThe compound proved insoluble in water, requiring the chemist to use an organic solvent instead.ModuleLevel 3RegistercontrastCollectionCollection 079SAT Complete planAlso in Collection 079threadbare, unremitting, incalculable, persevering, unpropitious, consanguine, thunderstruck, debar and 1 more