Full Idea
The fallacy of 'ad obscurum per obscurius' is to explain the obscure by appeal to what is more obscure.
Gist of Idea
It is a fallacy to explain the obscure with the even more obscure
Source
B Hale / C Wright (The Metaontology of Abstraction [2009], §3)
Book Reference
'Metametaphysics', ed/tr. Chalmers/Manley/Wasserman [OUP 2009], p.182
A Reaction
Not strictly a fallacy, so much as an example of inadequate explanation, along with circularity and infinite regresses.