German going round outside mill (7)
I believe the answer is:
grinder
'mill' is the definition.
(synonyms)
'german going round outside' is the wordplay.
'german' becomes 'ger' (abbreviation).
'going round' means one lot of letters goes inside another (some letters go around others).
'outside' becomes 'rind' (I've seen this before).
'ger' placed around 'rind' is 'GRINDER'.
(Other definitions for grinder that I've seen before include "Peppermill" , "Eg, pepper mill" , "organist?" , "Molar; miller" , "Mill; molar" .)