'Insoluble' definitions:

Definition of 'insoluble'

From: WordNet
adjective
(of a substance) incapable of being dissolved [syn: insoluble, indissoluble] [ant: soluble]
adjective
Admitting of no solution or explanation; "an insoluble doubt" [ant: soluble]
adjective
Without hope of solution; "an insoluble problem"

Definition of 'Insoluble'

From: GCIDE
  • Insoluble \In*sol"u*ble\, a. [L. insolubilis indissoluble, that can not be loosed: cf. F. insoluble. See In- not, and Soluble, and cf. Insolvable.] [1913 Webster]
  • 1. Not soluble; in capable or difficult of being dissolved, as by a liquid; as, chalk is insoluble in water. [1913 Webster]
  • 2. Not to be solved or explained; insolvable; as, an insoluble doubt, question, or difficulty. [1913 Webster]
  • 3. Strong. "An insoluble wall." [Obs.] --Holland [1913 Webster]