From Longman Dictionary of Contemporary Englishunbeliefun‧be‧lief /ˌʌnbəˈliːf/ noun [uncountable] literaryRR a lack of religious belief, or a refusal to believe in a religious faith → disbelief
Examples from the Corpus
unbelief• But the New Testament is strongly against doubt itself and stronger still against unbelief.• Blougram does not suggest that there is no difference between belief and unbelief.• The former can point to the great difference between doubt and unbelief and the latter to the great similarity.• And how is it related to faith and unbelief?• And Gabriel struck him dumb, for his unbelief.• Christians have stood firm against a flood of unbelief but have failed to notice its more subtle effects.• As faith is the opposite of unbelief, health is the opposite of death. 