Couturier has a mother for a model (7)
I believe the answer is:
diorama
'a model' is the definition.
(I've seen this before)
'couturier has a mother' is the wordplay.
'couturier' becomes 'dior' (I've seen this before).
'has' says to put letters next to each other.
'mother' becomes 'ma' (ma is a kind of mother).
'dior'+'a'+'ma'='DIORAMA'
'for' is the link.
(Other definitions for diorama that I've seen before include "3-D model representing a scene" , "Scenic picture" , "museum feature" , "AM radio? (anag)" , "picture that has depth" .)