That's good! Scoundrel's given up second home (5)
I believe the answer is:
dacha
'second home' is the definition.
(I know that dacha is a type of second home)
'that's good scoundrel's given up' is the wordplay.
'that's good' becomes 'ah' (I can't explain this - if you can you should give a lot more credence to this answer).
'scoundrel' becomes 'cad' (cad is a kind of scoundrel).
'given up' says the letters should be written backwards (in a down clue, letters go up).
'ah'+'cad'='ahcad'
'ahcad' in reverse letter order is 'DACHA'.
Can you help me to learn more?
(Other definitions for dacha that I've seen before include "Russian villa" , "Russian second home" , "Russian's second home in the country" , "A Russian country cottage" , "summer house" .)