Palladium rejected because screw contains iron (9)
I believe the answer is:
safeguard
'palladium' is the definition.
(thesaurus)
'rejected because screw contains iron' is the wordplay.
I cannot really understand how this works, but
'screw' could be 'guard' (I've seen this before) and 'guard' is present in the answer.
'iron' could be 'fe' (Fe is the chemical symbol for iron) and 'fe' is present in the answer.
The remaining letters 'sa' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for safeguard that I've seen before include "Protect" , "Preserve" , "Protective measure" .)