What puts off cleaner using hoover finally for good? (9)
I believe the answer is:
deterrent
'good?' is the definition.
Both the answer and definition are adjectives. Maybe there's an association between them I don't understand?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for deterrent that I've seen before include "Something designed to be off-putting" , "Something discouraging action" , "Weapon to discourage attack" , "Nuclear weapons allegedly" , "Tending to put off" .)