Clever commercial rubbish grabs one (6)
I believe the answer is:
adroit
'clever' is the definition.
(I've seen this before)
'commercial rubbish grabs one' is the wordplay.
'commercial' becomes 'ad'.
'rubbish' becomes 'rot' (I've seen this before).
'grabs' is an insertion indicator.
'one' becomes 'i' (Roman numeral).
'rot' going around 'i' is 'roit'.
'ad'+'roit'='ADROIT'
(Other definitions for adroit that I've seen before include "handy" , "resourceful" , "Deft and proficient" , "Dexterous, artful" , "skill" .)