Some joker educating backward boy (5)
I believe the answer is:
derek
'boy' is the definition.
'some joker educating backward' is the wordplay.
'some' indicates the answer is hidden within the clue (some parts of the word are used).
'backward' is a reversal indicator.
'kered' can be found hidden inside 'joker educating'.
'kered' backwards is 'DEREK'.
(Other definitions for derek that I've seen before include "Man's name" , "Fellow" , "- and the Dominos was Eric Clapton's band" , "Sir - - Jacobi (actor)" .)