Complicated detail, so withdrawn (8)
I believe the answer is:
isolated
'withdrawn' is the definition.
(thesaurus)
'complicated detail so' is the wordplay.
'complicated' indicates an anagram.
'detail'+'so'='detailso'
'detailso' with letters rearranged gives 'ISOLATED'.
(Other definitions for isolated that I've seen before include "Without accompaniment" , "Placed alone" , "Remote; lonely" , "Placed apart from others" , "hard to find" .)