Overseas budget's foremost, in a way (6)
I believe the answer is:
abroad
'overseas' is the definition.
('abroad' can be a synonym of 'overseas')
'budget's foremost in a way' is the wordplay.
'foremost' indicates taking the first letters.
'in' means one lot of letters goes inside another.
'way' becomes 'road' (road is a kind of way**).
The first letter of 'budgets' is 'b'.
'a'+'road'='aroad'
'b' going within 'aroad' is 'ABROAD'.
(Other definitions for abroad that I've seen before include "At large - overseas" , "Away from home" , "Out of doors - in foreign parts" , "At large; widely current" , "out of UK?" .)