Covered by legal document, actually (6)
I believe the answer is:
indeed
'actually' is the definition.
(thesaurus)
'covered by legal document' is the wordplay.
'covered' becomes 'in' (I've seen this in other clues).
'by' is a charade indicator (letters next to each other).
'legal document' becomes 'deed' (deed is a kind of legal document).
'in'+'deed'='INDEED'
(Other definitions for indeed that I've seen before include "Really, without doubt" , "Absolutely" , "Really - truly" , "To be sure" , "Really - what a surprise!" .)