Turn back extremely rude monster (4)
I believe the answer is:
ogre
'monster' is the definition.
(fairy tale monster)
'turn back extremely rude' is the wordplay.
'turn' becomes 'go' (a person's move in a board game).
'back' shows that the letters should be reversed in order.
'extremely' says to hollow out the word (remove centre letters) (only the extremes of the word are used).
'rude' with its middle removed is 're'.
'go' in reverse letter order is 'og'.
'og'+'re'='OGRE'
(Other definitions for ogre that I've seen before include "Giant who eats people" , "ugly one" , "One to gobble flesh" , "Cruel fairytale giant" , "Man-eating monster of fairy tales" .)