Unimaginative, having girl filling image (7)
I believe the answer is:
prosaic
'unimaginative' is the definition.
(I've seen this before)
'girl filling image' is the wordplay.
'girl' becomes 'rosa' (girl's name).
'filling' means one lot of letters goes inside another.
'image' becomes 'pic' (I've seen this before).
'rosa' placed into 'pic' is 'PROSAIC'.
'having' acts as a link.
(Other definitions for prosaic that I've seen before include "Is a crop (anag) - unimaginative" , "Dull (writing)" , "Lacking originality" , "Banal" , "Pedestrian, unimaginative" .)