A German, well-organised as an administrator (7)
I believe the answer is:
manager
'an administrator' is the definition.
(manager is a kind of administrator)
'a german well-organised' is the wordplay.
'well organised' indicates an anagram.
'a'+'german'='agerman'
'agerman' with letters rearranged gives 'MANAGER'.
'as' acts as a link.
(Other definitions for manager that I've seen before include "One in charge of sports team" , "Sports team runner" , "Decision-maker" , "who tries to cope?" , "Director" .)