Country house and home linked with unknown criminality (8)
I believe the answer is:
villainy
'criminality' is the definition.
(I've seen this before)
'country house and home linked with unknown' is the wordplay.
'country house' becomes 'villa' (villa is a kind of country house).
'and' says to put letters next to each other.
'home' becomes 'in' ('he's home' can mean 'he's in').
'linked with' means one lot of letters go next to another.
'unknown' becomes 'y' (algebra).
'villa'+'in'+'y'='VILLAINY'
(Other definitions for villainy that I've seen before include "Wicked behaviour" , "foul play" , "Criminality" , "Vile behaviour, evil act" , "Wickedness" .)