Report vagrant waylaying individual (7)
I believe the answer is:
'report' is the definition.
(I've seen this before)
'vagrant waylaying individual' is the wordplay.
'vagrant' becomes 'dosser' (informal term for a vagrant).
'waylaying' indicates putting letters inside (inserted letters are held or waylaid).
'individual' becomes 'i' (Roman numeral for one).
'dosser' enclosing 'i' is 'DOSSIER'.
(Other definitions for dossier that I've seen before include "File of documents" , "Collection of documents on a topic" , "Record" , "Set of papers" , "Papers containing detailed information about a particular person" .)