Series of cheeky devils turned over bank (4)
I believe the answer is:
dyke
'bank' is the definition.
'series of cheeky devils turned' is the wordplay.
'series of' indicates the answer is hidden within the clue (a series of letters from the clue).
'turned' says the letters should be written backwards.
'ekyd' can be found hidden inside 'cheeky devils'.
'ekyd' backwards is 'DYKE'.
'over' is the link.
(Other definitions for dyke that I've seen before include "Ditch; embankment" , "Flood defence" , "Embankment raised to prevent flooding" , "Flood barrier" , "Dam" .)