Spies chest buried by Poles (5)
I believe the answer is:
narks
'spies' is the definition.
The definition and answer can be both people as well as being plural nouns.
Perhaps there's an association between them I don't understand?
'chest buried by poles' is the wordplay.
'chest' becomes 'ark' (historical term for a chest).
'buried by' means one lot of letters goes inside another.
'poles' becomes 'ns' (north and south poles).
'ark' put into 'ns' is 'NARKS'.
Can you help me to learn more?
(Other definitions for narks that I've seen before include "singers" , "Irritates" , "Annoys; informers (sl.)" , "Coppers' ..... are slang police informers" .)