One paid to say nothing (5)
I believe the answer is:
extra
'one' is the definition.
Both the definition and answer are adjectives. Perhaps there's an association between them I don't understand?
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for extra that I've seen before include "particularly" , "Unnecessary" , "Additional expense" , "no ball perhaps" , "Exceptionally" .)