Vagrant crossing island for papers (7)
I believe the answer is:
dossier
'papers' is the definition.
(thesaurus)
'vagrant crossing island' is the wordplay.
'vagrant' becomes 'dosser' (informal term for a vagrant).
'crossing' is an insertion indicator.
'island' becomes 'i'.
'dosser' enclosing 'i' is 'DOSSIER'.
'for' acts as a link.
(Other definitions for dossier that I've seen before include "Collection of documents on a subject" , "Record" , "brief" , "Papers containing detailed information about a particular person" , "Set of papers" .)