Love affair, with fabulous bird enthralling chap, European (7)
I believe the answer is:
romance
'love affair' is the definition.
(I know that love affair can be written as romance)
'fabulous bird enthralling chap european' is the wordplay.
'fabulous bird' becomes 'roc' (mythical or fabulous giant bird).
'enthralling' means one lot of letters goes inside another.
'chap' becomes 'man' (chap can mean a man).
'european' becomes 'E' (abbreviation e.g. EU).
'roc' placed around 'man' is 'romanc'.
'romanc'+'e'='ROMANCE'
'with' acts as a link.
(Other definitions for romance that I've seen before include "(Wonderful) piece of fiction" , "marriage?" , "Novel - affair" , "Language group; love affair" , "fairy story?" .)