Corporation lawyer on top with information (5)
I believe the answer is:
datum
'information' is the definition.
(datum is a kind of information)
'corporation lawyer on top' is the wordplay.
'corporation' becomes 'tum' (I've seen this before).
'lawyer' becomes 'da' (D.A. is an example).
'on top' is a charade indicator (letters next to each other) (down clues only).
'tum' after 'da' is 'DATUM'.
'with' acts as a link.
(Other definitions for datum that I've seen before include "Single informative fact" , "Given item" , "Premiss, thing taken for granted" , "Minimal information" , "Fact or stat" .)