Superficial account found in dossier (6)
I believe the answer is:
facile
'superficial' is the definition.
(similar in meaning)
'account found in dossier' is the wordplay.
'account' becomes 'ac' (abbreviation for account).
'found in' is an insertion indicator.
'dossier' becomes 'file' (I've seen this in another clue).
'ac' placed inside 'file' is 'FACILE'.
(Other definitions for facile that I've seen before include "A piece of cake" , "Over-simple, superficial" , "Easy to accomplish" , "Lacking depth, glibly superficial" , "Smooth" .)