Insoluble
Insoluble , adjective
[Latin insolubilis indissoluble, that can not be loosed: compare French insoluble. See In- not, and Soluble, and compare Insolvable.]
1.
Not soluble; in capable or difficult of being dissolved, as by a liquid; as, chalk is insoluble in water.
2.
Not to be solved or explained; insolvable; as, an insoluble doubt, question, or difficulty.
3.
Strong. [Obsolete]
An insoluble wall.