Monk securing poor grade in spelling competition (4)
I believe the answer is:
bede
'monk' is the definition.
(I've seen this before)
'poor grade in spelling competition' is the wordplay.
'poor grade' becomes 'D' (an exam result).
'in' means one lot of letters goes inside another.
'spelling competition' becomes 'bee' (I've seen this in another clue).
'd' inserted into 'bee' is 'BEDE'.
'securing' is the link.
(Other definitions for bede that I've seen before include "Adam ___, novel by George Eliot" , "old monk" , "Authority consulted on English history" , "Adam, novel name" , "Venerable English saint" .)