Country cottage, one with central heating, secured by US lawyer (5)
I believe the answer is:
dacha
'country cottage' is the definition.
(I've seen this before)
'one with central heating secured by us lawyer' is the wordplay.
'one' becomes 'a' (a thing is one thing).
'with' means one lot of letters go next to another.
'central heating' becomes 'ch'.
'secured by' means one lot of letters goes inside another (inserted letters are held or secured).
'us lawyer' becomes 'DA' (abbreviation for District Attorney).
'a'+'ch'='ach'
'ach' going inside 'da' is 'DACHA'.
(Other definitions for dacha that I've seen before include "Second home in the country for Muscovites?" , "property overseas" , "summer house" , "Russian villa" , "A Russian country cottage" .)