aatheist

From a- + atheist, a negation of a negation. Technically (and disregarding this word's informality and humorousness), it should have been “anatheist”, with the euphonious prevocalic alpha privative (i.e., an-), from Ancient Greek ἀν- (an-); compare anaesthesia (from an- + aesthesia), anarchy, anorexia, and anaerobic.

1. 01
   derived from ἄθεος
2. 02
   derived from atheos
3. 03
   borrowed from athéiste
4. 04
   formed as aatheist — “a- + atheist”