US prosecutor entertaining a “companion” in country house (5)
I believe the answer is:
dacha
'country house' is the definition.
(dacha is a kind of country house)
'us prosecutor entertaining a companion' is the wordplay.
'us prosecutor' becomes 'da' (district attorney).
'entertaining' indicates putting letters inside.
'companion' becomes 'ch' (I've seen this in other clues).
'a'+'ch'='ach'
'da' enclosing 'ach' is 'DACHA'.
'in' acts as a link.
(Other definitions for dacha that I've seen before include "summer house" , "Russian's second home in the country" , "Second home in the country for Muscovites?" , "Russian retreat" , "Russian villa" .)