The story
- Latin · derived frominsolūbilis
- Middle French · derived frominsoluble
- Middle English · inherited frominsolible
- English todayinsoluble
From Middle English insolible, from Middle French insoluble, from Latin insolūbilis, from in- + solūbilis. Piecewise doublet of insolvable and unsolvable. By surface analysis, in- + soluble.
Etymology from Wiktionary, CC BY-SA 4.0.