Lie high-class religious books near Old Testament book (7)
I believe the answer is:
untruth
'lie' is the definition.
(an untruth is a lie)
'high-class religious books near old testament book' is the wordplay.
'high class' becomes 'U' (as in U and non-U speech).
'religious books' becomes 'NT' (New Testament).
'near' is a charade indicator (letters next to each other).
'old testament book' becomes 'Ruth' (Ruth is a book of the Old Testament).
'u'+'nt'+'ruth'='UNTRUTH'
(Other definitions for untruth that I've seen before include "Fib" , "story" , "A genuinely deniable" , "product of Orwell's ministry?" , "Fiction" .)