Clever head of Apple taking on Doctor of New Technology (6)
I believe the answer is:
adroit
'clever' is the definition.
(I've seen this before)
'head of apple taking on doctor of new technology' is the wordplay.
'head of' indicates taking the first letters.
'taking on' is a charade indicator (letters next to each other).
'doctor' becomes 'dr' ('Dr' can be a synonym of 'doctor').
'of' becomes 'o'.
'new technology' becomes 'it' (information technology).
The initial letter of 'apple' is 'a'.
'a'+'dr'+'o'+'it'='ADROIT'
(Other definitions for adroit that I've seen before include "Skilful, dexterous" , "Quick and clever in action or thought" , "Dexterous, artful" , "To raid (anag)" , "Nimble and skilful" .)