Posh criminal to quietly take shelter in compound (9)

I believe the answer is:

phosphide

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'compound' is the definition.
Both the definition and answer are singular nouns.
Perhaps you can see a link between them that I can't see?

'posh criminal to quietly take shelter' is the wordplay.
'criminal' is an anagram indicator.
'to quietly' becomes 'p' (p for piano and quiet).
'take' means one lot of letters go next to another.
'shelter' becomes 'hide' (I've seen this before).
'posh' is an anagram of 'phos'.
'phos'+'p'+'hide'='PHOSPHIDE'

'in' is the link.

Can you help me to learn more?

I've seen this clue in The Hindu.

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