Stoop to providing an incomplete design (5)
I believe the answer is:
deign
'stoop to' is the definition.
(I've seen this in another clue)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for deign that I've seen before include "Do something that's below one's dignity" , "Lower oneself" , "Think fit" , "Think appropriate" , "Condescend; stoop" .)