Put down false name in legal document (8)
I believe the answer is:
demeaned
'put down' is the definition.
(I've seen this before)
'false name in legal document' is the wordplay.
'false' indicates anagramming the letters.
'in' is an insertion indicator.
'legal document' becomes 'deed' (deed is a kind of legal document).
'name' with letters rearranged gives 'mean'.
'mean' placed inside 'deed' is 'DEMEANED'.
(Other definitions for demeaned that I've seen before include "Given lower status" , "Lowered in status or reputation" , "Degraded, put down" , "Lowered in dignity or reputation" , "Humiliated" .)