Non-water-soluble is a term that is frequently used to describe substances or materials that cannot be dissolved or absorbed in water. However, there are several synonyms that can be used interchangeably with non-water-soluble. These include insoluble, immiscible, resistant, impermeable, and non-dissolvable. Insoluble is a common term for something that cannot dissolve in a particular solvent, while immiscible implies two substances that are unable to mix. Resistance refers to the inability of a material to be penetrated or affected by a particular phenomenon. Impermeable means that a substance cannot be penetrated or passed through, while non-dissolvable simply means something cannot be dissolved or liquefied in a particular solvent.