Unfathomable
Unfathomable adjective - Impossible to understand.
Usage example: for some unfathomable reason the family decided to venture out into the blizzard
Unimaginable and unfathomable are semantically related. In some cases you can use "Unimaginable" instead an adjective "Unfathomable".
Unimaginable
Unimaginable adjective - Too extraordinary or improbable to believe.
Unfathomable and unimaginable are semantically related. Sometimes you can use "Unfathomable" instead an adjective "Unimaginable".
Mutual synonyms
Cite this Source
Unimaginable and Unfathomable. (2016). Retrieved 2026, July 28, from https://thesaurus.plus/related/unfathomable/unimaginable
Unfathomable & Unimaginable. N.p., 2016. Web. 28 Jul. 2026. <https://thesaurus.plus/related/unfathomable/unimaginable>.
Unimaginable or Unfathomable. 2016. Accessed July 28, 2026. https://thesaurus.plus/related/unfathomable/unimaginable.
Google Ngram Viewer shows how "unfathomable" and "unimaginable" have occurred on timeline