Corporation lawyer is first to get information (5)
I believe the answer is:
datum
'information' is the definition.
(datum is a kind of information)
'corporation lawyer is first' is the wordplay.
'corporation' becomes 'tum' (I've seen this before).
'lawyer' becomes 'da' (D.A. is an example).
'is first' says to put letters next to each other.
'tum' put after 'da' is 'DATUM'.
'to get' acts as a link.
(Other definitions for datum that I've seen before include "Fixed starting point for measurements" , "Something given" , "Little bit of information" , "Given item" , "Fact or stat" .)