Walk purposefully over books in grating? (8)
I believe the answer is:
strident
'grating?' is the definition.
(thesaurus)
'walk purposefully over books' is the wordplay.
'walk purposefully' becomes 'stride'.
'over' is a charade indicator (letters next to each other).
'books' becomes 'nt' (New Testament).
'stride'+'nt'='STRIDENT'
'in' acts as a link.
(Other definitions for strident that I've seen before include "Loud and vociferous" , "Harsh in tone" , "Roaring" , "With a loud, harsh voice" , "Clamorous" .)