Book encapsulates withdrawn broadcast item (7)
I believe the answer is:
twosome
'item' is the definition.
(I've seen this before)
'book encapsulates withdrawn broadcast' is the wordplay.
'book' becomes 'tome' (a tome is a book).
'encapsulates' is an insertion indicator.
'withdrawn broadcast' becomes 'wos' (I can't justify this - if you can you should believe this answer much more).
'tome' going around 'wos' is 'TWOSOME'.
Can you help me to learn more?
(Other definitions for twosome that I've seen before include "game of golf" , "Item" , "match" , "Couple" , "Pair, duo" .)