Master sliced duck being a genius (7)
I believe the answer is:
maestro
'a genius' is the definition.
(I've seen this before)
'master sliced duck' is the wordplay.
'sliced' indicates anagramming the letters.
'duck' becomes 'o' (resembles zero - 'duck' in cricket).
'master' with letters rearranged gives 'maestr'.
'maestr'+'o'='MAESTRO'
'being' acts as a link.
(Other definitions for maestro that I've seen before include "great musician" , "best in field" , "Orchestral conductor" , "Noted conductor" , "Top music man" .)