The foreign editor, in plush surroundings (7)
I believe the answer is:
swedish
'plush surroundings' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'the foreign editor in' is the wordplay.
'the foreign' becomes 'swish' (I can't justify this - if you can you should give a lot more credence to this answer).
'editor' becomes 'ed' (abbreviation).
'in' is an insertion indicator.
'swish' enclosing 'ed' is 'SWEDISH'.
Can you help me to learn more?
(Other definitions for swedish that I've seen before include "Nationality that swished around" , "from European country" , "From Uppsala, perhaps" , "Soprano Jenny Lind, b. Stockholm 1798, d. Herefordshire 1887" , "Nordic" .)