We don't have synonyms for aseity yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are seity, gaseity and asity.
(n) :
(metaphysics, theology) Usually ascribed to deity: the attribute of being entirely self-derived, in contrast to being derived from or dependent on another; the quality of having within oneself the entire reason for one's being; utter independent self-existence and self-sustenance.
(n) :
(metaphysics, theology) Usually ascribed to deity: the attribute of being entirely self-derived, in contrast to being derived from or dependent on another; the quality of having within oneself the entire reason for one's being; utter independent self-existence and self-sustenance.