Subterranean cell: muck one out (7)

I believe the answer is:

dungeon

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'subterranean cell' is the definition.
'dungeon' can be an answer for 'cell' (underground cell). I am not sure about the 'subterranean' bit.

'muck one out' is the wordplay.
'muck' becomes 'dung' (synonyms).
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'one' anagrammed gives 'eon'.
'dung'+'eon'='DUNGEON'

Can you help me to learn more?

(Other definitions for dungeon that I've seen before include "Dark prison cell" , "Uncongenial accommodation" , "Underground prison-cell" , "Keep" , "prison the result" .)

I've seen this clue in The Sun.

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