- Not soluble; in capable or difficult of being dissolved,
as by a liquid; as, chalk is insoluble in water. - Not to be solved or explained; insolvable; as, an
insoluble doubt, question, or difficulty. - Strong.
Meaning of 'insoluble' (Princeton's WordNet)
1 . insoluble
[ a]
Meaning (1): - admitting of no solution or explanation