Changing euro next, as foreign (10)
I believe the answer is:
extraneous
'foreign' is the definition.
('extraneous' can be a synonym of 'foreign')
'changing euro next as' is the wordplay.
'changing' indicates anagramming the letters.
'euro'+'next'+'as'='euronextas'
'euronextas' anagrammed gives 'EXTRANEOUS'.
(Other definitions for extraneous that I've seen before include "Unrelated to the subject" , "Unrelated, irrelevant" , "not essential" , "Irrelevant; of outside origin" , "Not belonging" .)