Hellacious
Hellacious adjective - Requiring considerable physical or mental effort.
Usage example: the pioneers survived a particularly hellacious river crossing with their covered wagon barely in one piece
Insoluble and hellacious are semantically related. In some cases you can use "Insoluble" instead an adjective "Hellacious".
Insoluble
Insoluble adjective - Incapable of being solved or accomplished.
Hellacious and insoluble are semantically related. Sometimes you can use "Hellacious" instead an adjective "Insoluble".
Nearby Word: insolubility
Cite this Source
Insoluble and Hellacious. (2016). Retrieved 2026, July 21, from https://thesaurus.plus/related/hellacious/insoluble
Hellacious & Insoluble. N.p., 2016. Web. 21 Jul. 2026. <https://thesaurus.plus/related/hellacious/insoluble>.
Insoluble or Hellacious. 2016. Accessed July 21, 2026. https://thesaurus.plus/related/hellacious/insoluble.
Google Ngram Viewer shows how "hellacious" and "insoluble" have occurred on timeline