Supervise poetry being put into Old English (7)
I believe the answer is:
oversee
'supervise' is the definition.
(I know that supervise can be written as oversee)
'poetry being put into old english' is the wordplay.
'poetry' becomes 'verse' (synonyms).
'being put into' indicates putting letters inside.
'old english' becomes 'oe'.
'verse' going into 'oe' is 'OVERSEE'.
(Other definitions for oversee that I've seen before include "Keep a check on" , "What superintendent will do" , "Superintend, manage" , "Supervise, control" , "Supervise, keep an eye on" .)