A merchant's intelligence taking a long time on book (9)
I believe the answer is:
newsagent
'a merchant's' is the definition.
(newsagent is a kind of merchant)
'intelligence taking a long time on book' is the wordplay.
I cannot really understand how this works, but
'intelligence' could be 'news' (synonyms) and 'news' is found in the answer.
'time' could be 'age' (an age is a period of time) and 'age' is located in the answer.
'book' could be 'nt' (New Testament) and 'nt' is located in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for newsagent that I've seen before include "Retailer" , "Guardian seller?" , "daily shop" , "Shopkeeper selling magazines" , "shop selling rags?" .)