Grand house in very bad area (5)
I believe the answer is:
villa
'grand house' is the definition.
'villa' can be an answer for 'house' (villa is a kind of house). I'm not sure about the 'grand' bit.
'very bad area' is the wordplay.
'very' becomes 'v' (common abbreviation).
'bad' becomes 'ill' (associated in meaning).
'area' becomes 'a' (maths abbreviation).
'v'+'ill'+'a'='VILLA'
'in' is the link.
Can you help me to learn more?
(Other definitions for villa that I've seen before include "Country house (in Aston?)" , "Country house in Italy or France" , "SECOND PART OF 8" , "Classical country house" , "Midlands football team" .)