Old forward is back in style, showing adroitness (9)
I believe the answer is:
expertise
'adroitness' is the definition.
(I've seen this before)
'old forward is back in style' is the wordplay.
'old' becomes 'ex'.
'forward' becomes 'pert' (I've seen this in other clues).
'back in' suggests the final letters (the 'back' of the word).
The final letter of 'style' is 'e'.
'ex'+'pert'+'is'+'e'='EXPERTISE'
'showing' is the link.
(Other definitions for expertise that I've seen before include "Thorough knowledge" , "Adroitness" , "Technical skill" , "Craft" , "Special skill or knowledge" .)