Big, lean rough European (7)
I believe the answer is:
belgian
'european' is the definition.
(I know that Belgian is a type of european)
'big lean rough' is the wordplay.
'rough' indicates anagramming the letters (a rough or broken ordering of the letters).
'big'+'lean'='biglean'
'biglean' is an anagram of 'BELGIAN'.
(Other definitions for belgian that I've seen before include "Hercule Poirot's nationality" , "One from Liege, say" , "Nationality of Rene Magritte" , "Eg, Brussels native" , "Bengali from a European state?" .)