Very few oxymorons actually derive their humour from the dictionary definitions of the words involved. It's the combination of the words together with their less common meanings which usually makes them funny.

From that standpoint a confirmed atheist is indeed oxymoronic.

I have always like the term "permanent prehostility" which is not an oxymoron but which is a term used in CIA double-speak to mean "peace".

Can anyone come up with an oxymoron which is also a tautology? "Criminal lawyer" is close but not close enough for the cigar.

- Pfranz