Supervise some poetry in Old English (7)
I believe the answer is:
oversee
'supervise' is the definition.
('oversee' can be a synonym of 'supervise')
'some poetry in old english' is the wordplay.
'some poetry' becomes 'verse' ('verse' can be a synonym of 'poetry').
'in' means one lot of letters goes inside another.
'old english' becomes 'oe'.
'verse' put into 'oe' is 'OVERSEE'.
(Other definitions for oversee that I've seen before include "Supervise, manage" , "Exercise supervision" , "What superintendent will do" , "Supervise officially" , "Supervise, keep an eye on" .)