Theft of extremely fine cloth hidden by mansion? (9)
I believe the answer is:
pilferage
'theft' is the definition.
(pilferage is a kind of theft)
'extremely fine cloth hidden by mansion?' is the wordplay.
'extremely' suggests removing the centre (only the extremes of the word are used).
'cloth' becomes 'rag' (rag is a kind of cloth).
'hidden by' is an insertion indicator (inserted letters are hidden inside).
'mansion?' becomes 'pile' (pile can mean a large building).
'fine' with its middle taken out is 'fe'.
'fe'+'rag'='ferag'
'ferag' going into 'pile' is 'PILFERAGE'.
'of' is the link.
(Other definitions for pilferage that I've seen before include "Theft (of small items)" , "Petty theft" , "Minor stealing" , "Thefts" .)