Polish duke in twisted relationship (4)
I believe the answer is:
edit
'polish' is the definition.
(I've seen this in another clue)
'duke in twisted relationship' is the wordplay.
'duke' becomes 'd' (abbreviation).
'in' indicates putting letters inside.
'twisted' says the letters should be written in reverse.
'relationship' becomes 'tie' (tie is a kind of relationship).
'tie' reversed gives 'eit'.
'd' inserted within 'eit' is 'EDIT'.
(Other definitions for edit that I've seen before include "Rewrite" , "Prepare (material) for publication" , "Prepare text for press" , "be a bookmaker" , "Prep for press" .)