What does insoluble mean?
Insoluble means unable to dissolve in a liquid. The term is commonly used in chemistry, biology, materials science, and environmental science to describe substances that do not break down evenly in a particular solvent. For example, a substance may be described as insoluble in water but soluble in alcohol. Insoluble can also be used figuratively for a problem, disagreement, or mystery that cannot be easily resolved or explained. In this sense, it suggests more than temporary difficulty: the matter may have no straightforward solution. The word is precise and technical in its literal meaning, while its figurative use is formal but widely understood. Because a substance can be insoluble in one solvent and soluble in another, specifying the liquid is important when using the term accurately.
adjectiveIncapable of dissolving in a liquid. In figurative use, unable to be resolved or settled.
- Not able to dissolve in a liquid.
- Unable to be resolved, settled, or explained.
"The coating remained insoluble, making the material difficult to clean."
"The powder was insoluble in both water and oil."
"The committee struggled with the insoluble problems of the dispute."
What looks like one solid substance can contain a world of molecules that refuse to dissolve.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does insoluble come from?
Insoluble comes from Latin insolubilis, formed from the prefix in-, meaning “not,” and solubilis, meaning “able to be dissolved.” The Latin root is related to solvere, “to loosen, dissolve, or solve.” English borrowed the word in the early modern period, initially in scientific writing, and later extended it to figurative problems that cannot be solved.
Related word forms
How insoluble is actually used
In scientific and technical contexts, it is usually followed by the solvent: “insoluble in water.” Figurative uses, such as “an insoluble problem,” mean that a matter cannot readily be resolved.
Easily confused with insoluble
Soluble means capable of dissolving, whereas insoluble means incapable of dissolving.