Synonyms for insoluble

Adjective

1. insoluble (vs. soluble), indissoluble

usage: (of a substance) not easily dissolved

2. insoluble (vs. soluble), insolvable, unsoluble, unsolvable, unresolvable, inexplicable#1, incomprehensible

usage: admitting of no solution or explanation; "an insoluble doubt"

3. insoluble, hopeless (vs. hopeful)

usage: without hope of solution; "an insoluble problem"