Duke's wife anticipated endless game (7)
I believe the answer is:
duchess
'duke's wife' is the definition.
(I've seen this before)
'anticipated endless game' is the wordplay.
'anticipated' becomes 'due' ('due' can be similar in meaning to 'anticipated').
'endless' means to remove the last letter.
'game' becomes 'chess' (chess is a kind of game).
'due' with its final letter taken off is 'du'.
'du'+'chess'='DUCHESS'
(Other definitions for duchess that I've seen before include "Female aristocrat" , "Duke's wife" , "Wife of a duke" , "Titled lady" , "Noble lady" .)