Unbeliever (8)
'unbeliever' is the definition.
(atheist is a kind of unbeliever)
This is the entire clue.
(Other definitions for atheist that I've seen before include "One doesn't believe" , "One who does not believe in the existence of a god" , "One denies the existence of gods" , "I don't believe" , "Person who does not believe in existence of a god" .)
'unbeliever' is the definition.
(I know that unbeliever can be written as infidel)
This is all the clue.
(Other definitions for infidel that I've seen before include "Disbeliever" , "I don't believe" , "Sceptical" , "Non-believer, heretic" , "Someone who does not acknowledge your god" .)
(Other definitions for sceptic that I've seen before include "Greek philosopher" , "Doubter; atheist" , "One questioning accepted opinions" , "Disbeliever" , "Thomas for one" .)
'unbeliever' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for heretic that I've seen before include "One with unorthodox opinions" , "Person with views contrary to accepted beliefs" , "One breaking with orthodox beliefs" , "Misbeliever" , "Unorthodox believer" .)
(Other definitions for agnostic that I've seen before include "Doubter - coatings (anag)" , "One who is undecided" , "Religiously non-commital" , "Uncertain type" , "Coasting with unbeliever" .)