Insoluble

This is insoluble in water.

Aluminium is insoluble in water.

Anyone who does not have tools always finds the slightest problem insoluble.

The alveoli are normally stabilized against collapse by the presence of inert and relatively insoluble gas (nitrogen) and an internal coating of lipoprotein substances with low surface tension.

Petroleum is largely insoluble in water.

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.

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

As there is a partial vacuum inside the drum, the liquid is sucked inside the drum and the insolubles are deposited on the outer surface of the membrane filter.