Take away from, by deed, half the land (7)
I believe the answer is:
detract
'take away from' is the definition.
(thesaurus)
'by deed half the land' is the wordplay.
'by' is a charade indicator (letters next to each other).
'half' indicates taking half.
'the land' becomes 'tract' (I've seen this in other clues**).
'deed' cut in half is 'de'.
'de' put next to 'tract' is 'DETRACT'.
(Other definitions for detract that I've seen before include "Take away (from worth)" , "Slight" , "Take away (from value of something)" , "Take away, character perhaps" , "Derogate" .)