America, Soviet Union, most of Ireland, Sweden initially and those down under shortly (7)
I believe the answer is:
aussies
'those down under shortly' is the definition.
I can't judge whether this defines the answer.
'america soviet union most of ireland sweden initially' is the wordplay.
'america' becomes 'a' (common abbreviation - e.g. in organisation names).
'soviet union' becomes 'USSR' (synonyms).
'most of' means to remove the last letter.
'ireland' becomes 'ie' (two letter country code).
'initially' indicates taking the first letters.
The first letter of 'sweden' is 's'.
'ussr' with its last letter taken away is 'uss'.
'a'+'uss'+'ie'+'s'='AUSSIES'
'and' is the link.
Can you help me to learn more?
(Other definitions for aussies that I've seen before include "Our Ashes opponents" , "Australians (colloq.)" , "Antipodeans, in short" , "Informal people from Down Under" , "Islanders" .)