insolubleness

From insoluble +‎ -ness.

insolubleness (uncountable)

1. The quality or state of being insoluble; insolubility.
   • 1672, Robert Boyle, “.] An Hydrostatical Discourse, Occasioned by the Objects of the Learned Dr. Henry More, against Some Explications of New Experiments Made by Mr. Boyle; and Now Published by Way of Preface to the Three Ensuing Tracts. Chapter V.”, in The Works of the Honourable Robert Boyle. , volume III, London: A Millar, , published 1744, →OCLC, section II, page 281, column 1:

     But that vve may the more diſtinctly conſider this grand argument, […] it vvill be convenient to obſerve, that it does, at once, both propoſe a queſtion, and contain an objection, grounded upon the ſurmiſed inſolubleneſs of that queſtion.

• “insolubleness”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.