Help with Strange Greek Word...

[pythagoras.lym]

I was reading Nicolaus Cusanus' De Principio and in it he references Proclus' Commentary on Plato's Parmenides. In the reference, he uses the word, α'υτοθεοτης. Also he uses another strange word α'υθυπόστατος I think these are Grammarian type words. Could someone please try to help with a rough meaning behind these strange words? Thanks.

[NateD26]

I think it'd be better to ask these kind of questions inside the Learning Greek section.

The first word, according to the LSJ, means very Godhead (uppercase = holy trinity?). seems to be the only place it'd been used.
The second means self-substantial. I've found 267 instances on the TLG database so I guess it's common enough.