Polished part of table between each set of books (7)
I believe the answer is:
elegant
'polished' is the definition.
(I've seen this before)
'part of table between each set of books' is the wordplay.
'part of table' becomes 'leg' ('leg' is part of 'table').
'between' indicates putting letters inside.
'each' becomes 'ea'.
'set of books' becomes 'nt' (New Testament).
'leg' going into 'ea' is 'elega'.
'elega'+'nt'='ELEGANT'
(Other definitions for elegant that I've seen before include "A gentle sort of stylish appearance" , "Cleverly simple" , "Debonair, stylishly dressed" , "Refined gracefulness" , "Graceful - refined" .)