An oxycretin is an obscure but self-evident contraindication.
An oxycretin is the direct opposition to what seems superficially plausible but on closer scrutiny reveals how the subliminal nuances actually are contrary to expectations.
An oxycretin is more subtle and not as blatant as the apparently obvious contradiction of an oxymoron.

Case in point: personal presence maybe just an imaginary figment of sentience ie. the ethereal personae is simply a vacuous and void substance of