Some information US lawyer used against corporation (5)
I believe the answer is:
datum
'some information' is the definition.
(datum is a kind of information)
'us lawyer used against corporation' is the wordplay.
'us lawyer' becomes 'da' (abbreviation for District Attorney).
'used against' says to put letters next to each other.
'corporation' becomes 'tum' (I've seen this before).
'da'+'tum'='DATUM'
(Other definitions for datum that I've seen before include "Bit of dope" , "given to the Romans" , "Given item" , "Fact or stat" , "Given fact" .)