Engine, perhaps, forbidden support for pieces (8)
I believe the answer is:
outboard
'engine' is the definition.
(I know that outboard is a type of internal combustion engine)
'forbidden support for pieces' is the wordplay.
I cannot really understand how this works, but
'forbidden' could be 'out' (synonyms) and 'out' is found in the answer.
The remaining letters 'board' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'perhaps' acts as a link.
Can you help me to learn more?
(Other definitions for outboard that I've seen before include "Engine external to the boat" , "Sort of motor" , "Small boat's motor" , "Engine attached to boat" , "Type of boat engine" .)