Let China clay initially be moulded by expert (9)
I believe the answer is:
technical
'expert' is the definition.
(I know that expert can be written as technical)
'let china clay initially be moulded' is the wordplay.
'initially' suggests taking the first letters.
'be moulded' indicates anagramming the letters.
The initial letter of 'clay' is 'c'.
'let'+'china'+'c'='letchinac'
'letchinac' with letters rearranged gives 'TECHNICAL'.
'by' acts as a link.
(Other definitions for technical that I've seen before include "Relating to mechanical art or applied science" , "Concerned with applied science" , "Concerned with applied sciences" , "Using specialised skill" , "- Drawing; - foul" .)