Doctor welcoming green colour scheme (5)
I believe the answer is:
decor
'colour scheme' is the definition.
(I've seen this before)
'doctor welcoming green' is the wordplay.
'doctor' becomes 'dr' ('Dr' can be a synonym of 'doctor').
'welcoming' is an insertion indicator (in sense of 'inviting in').
'green' becomes 'eco' (abbreviation for ecological).
'dr' enclosing 'eco' is 'DECOR'.
(Other definitions for decor that I've seen before include "Colour-scheme etc of a room" , "Interior layout and furnishings" , "Room colour scheme, furnishings, etc" , "ornament" , "Internal ornamentation" .)