Boris's wife, we hear, presuming to move to next position (5,7)
I believe the answer is:
carry forward
'move to next position' is the definition.
(move forward)
'boris's wife we hear presuming to' is the wordplay.
I cannot really see how this works, but
'wife' could be 'w' (abbreviation) and 'w' is found in the answer.
'to' could be 'for' and 'for' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for carry forward that I've seen is " figures".)