Embrace European of substantial proportions (4)
I believe the answer is:
huge
'of substantial proportions' is the definition.
(huge means substantial or large)
'embrace european' is the wordplay.
'embrace' becomes 'hug' (synonyms).
'european' becomes 'E' (abbreviation e.g. EU).
'hug'+'e'='HUGE'
(Other definitions for huge that I've seen before include "Enormous" , "Colossal" , "Unusually large" , "Mammoth" , "Massive" .)