Interior designer and lecturer behind at Christmas time (9)
I believe the answer is:
decorator
'interior designer' is the definition.
(synonyms)
'lecturer behind at christmas time' is the wordplay.
'lecturer behind' becomes 'orator' (I can't justify this - if you can you should give a lot more credence to this answer).
'at' is a charade indicator (letters next to each other) (I've seen this in other clues).
'christmas time' becomes 'dec' (short for Dec).
'orator' after 'dec' is 'DECORATOR'.
'and' is the link.
Can you help me to learn more?
(Other definitions for decorator that I've seen before include "Who paints" , "Artisan" , "Painter perhaps" , "One doing up a house or room" , "Handyman" .)