'antiatheist' originates from Greek and English elements: the prefix 'anti-' (from Greek 'antí') meaning 'against' combined with 'atheist' (from Greek 'atheos'), where 'a-' meant 'without' and 'theos' meant 'god'.

'atheist' comes from Greek 'atheos' which passed into Late Latin/Medieval Latin as 'atheista' and then into English as 'atheist'; the modern compound 'antiatheist' formed in English by combining 'anti-' + 'atheist'.

Initially it literally meant 'against atheists' or 'against atheism'; over time the term has continued to carry that basic sense and is used to describe persons, attitudes, or publications opposing atheism or atheists.