Enthusiast in EU with a tram in development (7)
I believe the answer is:
amateur
'enthusiast' is the definition.
(I've seen this before)
'eu with a tram in development' is the wordplay.
'with' means one lot of letters go next to another.
'in development' indicates an anagram.
'a'+'tram'='atram'
'eu' after 'atram' is 'atrameu'.
'atrameu' is an anagram of 'AMATEUR'.
'in' acts as a link.
(Other definitions for amateur that I've seen before include "A non-professional sportsman" , "One is not professional" , "Unpaid (sportsman}" , "Non-pro" , "Dilettante: buff" .)