Does sir muddle the papers? (7)
I believe the answer is:
dossier
'papers?' is the definition.
(I've seen this before)
'does sir muddle' is the wordplay.
'muddle' indicates an anagram.
'does'+'sir'='doessir'
'doessir' is an anagram of 'DOSSIER'.
'the' is the link.
(Other definitions for dossier that I've seen before include "Papers containing detailed information about someone" , "Collection of documents on a subject" , "File of documents" , "Report" , "Set of papers" .)