insoluble

What it means

1. physicalchemistryThat cannot be dissolved.

   Petroleum is largely insoluble in water.

   Synonyms: indissoluble, undissolvable · Antonyms: soluble, dissoluble, dissolvable

2. That cannot be solved.

   This dispute, as already stated was insoluble in the ideological context in which it took place.

   1978 [1976], Leszek Kołakowski, translated by P[aul] S[teven] Falla, Main Currents of Marxism, volume II: The Golden Age, Oxford: Clarendon Press, translation of Główne nurty marksizmu: rozwój (in Polish), →ISBN, →OCLC, page 253

   1 more example

   The reason Fisher concluded that the problem is likely insoluble is that the ability of real-world agents to act on new perceived opportunities of arbitrage – including those that turn out to be incorrect – makes stability impossible to demonstrate without additional strong (and unrealistic) assumptions.

   2024, Jeremy B. Rudd, A Practical Guide to Macroeconomics, page 3

   Synonyms: insolvable, unsolvable · Antonyms: soluble, solvable

3. That cannot be explained.

   Near-synonyms: unexplained, mysterious; see also Thesaurus:incomprehensible, Thesaurus:mysterious

   Synonyms: inexplicable, unexplainable, unexplained, mysterious, abstruse, Chinese, dense, enigmatic · Antonyms: soluble, solvable

In a sentence

Petroleum is largely insoluble in water.

Where it comes from

1. Latininsolūbilis
2. Middle Frenchinsoluble
3. Middle Englishinsolible
4. Englishinsoluble

From Middle English insolible, from Middle French insoluble, from Latin insolūbilis, from in- + solūbilis. Piecewise doublet of insolvable and unsolvable. By surface analysis, in- + soluble.