Standing and helping to hold book (7)
I believe the answer is:
abiding
'standing' is the definition.
('abide' can be a synonym of 'stand')
'helping to hold book' is the wordplay.
'helping' becomes 'aiding' ('aid' can be a synonym of 'help'**).
'to hold' is an insertion indicator.
'book' becomes 'b'.
'aiding' enclosing 'b' is 'ABIDING'.
'and' is the link.
(Other definitions for abiding that I've seen before include "Permanent" , "With a lasting quality" , "Putting up with: long-lasting" , "standing" , "Durable, lasting" .)