Noun
One who justifies; one who vindicates, supports, defends, or absolves.
Source: Webster's dictionaryan apologist for capital punishment Source: Internet
At least sometimes, the justifier of a belief is another belief. Source: Internet
If a belief is justified, then it has at least one justifier. Source: Internet
Regardless, to be justified, a belief has to have a justifier. Source: Internet
Thus, such a belief is unjustified because the justifier on which it depends is itself not justified. Source: Internet