Part of a watch that cannot be new (10)
I believe the answer is:
secondhand
'part of a watch that cannot be new' is the definition.
Both the answer and definition are adjectives. Maybe there's a link between them I don't understand?
'part' is the wordplay.
I cannot quite understand how this works, but
'part' could be 'hand' (hand is a kind of part) and 'hand' is located in the answer.
The remaining letters 'second' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for secondhand that I've seen before include "feature on a watch" , "Used" .)