Possibly dubious bachelor request left in bottom of file (10)
I believe the answer is:
borderline
'possibly dubious' is the definition.
(borderline can mean dubious or unclear)
'bachelor request left in bottom of file' is the wordplay.
'bachelor' becomes 'B' (abbreviation e.g. BA=Bachelor of Arts).
'request' becomes 'order' (an order is a request from someone in authority).
'left in bottom of file' becomes 'line' (I can't explain this - if you can you should give a lot more credence to this answer).
'b'+'order'+'line'='BORDERLINE'
(Other definitions for borderline that I've seen before include "barely acceptable" , "Boundary" , "frontier" , "Marginal n" , "divides countries" .)