Book European obtains free -- The Woman in White? (5)
I believe the answer is:
bride
'woman in white?' is the definition.
(brides traditionally wear white)
'book european obtains free' is the wordplay.
'book' becomes 'b' (abbreviation for book).
'european' becomes 'e' (abbreviation e.g. EU).
'obtains' means one lot of letters goes inside another.
'free' becomes 'rid' (to be free of something is to be rid of it).
'b'+'e'='be'
'be' placed around 'rid' is 'BRIDE'.
'the' is the link.
(Other definitions for bride that I've seen before include "Wife of groom" , "One getting married" , "new union member" , "Wedding day woman" , "woman in front of train" .)