Undermine plan to return Argentine parts (6)
I believe the answer is:
pampas
'argentine parts' is the definition.
The answer and definition can be both locations as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'undermine plan to return' is the wordplay.
'undermine' becomes 'sap' (I've seen this before).
'plan' becomes 'map' (I've seen this before).
'to return' is a reversal indicator.
'sap'+'map'='sapmap'
'sapmap' back-to-front is 'PAMPAS'.
Can you help me to learn more?
(Other definitions for pampas that I've seen before include "South American plains" , "Plains with grass" , "South American plain" , "Vast plains of South America" , "Great plains of Argentina" .)