Locks securing books and eyewash (3,3)
I believe the answer is:
hot air
'eyewash' is the definition.
(both can mean nonsense)
'locks securing books' is the wordplay.
'locks' becomes 'hair' (locks can mean hair).
'securing' means one lot of letters goes inside another.
'books' becomes 'OT' (Old Testament).
'hair' placed around 'ot' is 'HOT-AIR'.
'and' acts as a link.
(Other definitions for hot air that I've seen before include "Talking nonsense" , "Gas" , "Bluster" , "Bombastic talk or balloon elevator" , "Bombast or balloon filler" .)