Ditch cheeky Dadaist exhibits, upon reflection (4)
I believe the answer is:
dyke
'ditch' is the definition.
(I've seen this before)
'cheeky dadaist exhibits upon reflection' is the wordplay.
'exhibits' says the answer is hidden in the clue.
'upon reflection' says the letters should be written in reverse.
'ekyd' is hidden within 'cheeky dadaist'.
'ekyd' backwards is 'DYKE'.
(Other definitions for dyke that I've seen before include "Dick Van - - (films)" , "Barrier to prevent flooding" , "Ditch; earthwork" , "Flood embankment" , "Dam" .)