My delicate decorative feature (7)
I believe the answer is:
cornice
'decorative feature' is the definition.
(I've seen this before)
'my delicate' is the wordplay.
'my' becomes 'cor' (both are expressions of surprise).
'delicate' becomes 'nice' (I am not sure about this - if you are sure you should believe this answer much more).
'cor'+'nice'='CORNICE'
Can you help me to learn more?
(Other definitions for cornice that I've seen before include "decorative part of room" , "Ledge of snow overhanging a precipice" , "Overhanging ledge of frozen snow" , "decorative feature" , "Moulding along top of building" .)