Gosh, a number coming to ruin in the country (7)
I believe the answer is:
myanmar
'the country' is the definition.
(Myanmar is an example)
'gosh a number coming to ruin' is the wordplay.
'gosh' becomes 'my' (both are old-fashioned expressions of surprise).
'number' becomes 'n' (n can represent any number).
'coming to' means one lot of letters go next to another.
'ruin' becomes 'mar' (I've seen this before).
'my'+'a'+'n'+'mar'='MYANMAR'
'in' is the link.
(Other definitions for myanmar that I've seen before include "Far East location" , "Another name for Burma" , "Army man in new Burma" , "Modern name for Burma" , "Yangon is its capital" .)