Sort out one's trunks (5)

I believe the answer is:

torsi

'trunks' is the definition.
('torso' can be a synonym of 'trunk')

'sort out one's' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'one' becomes 'i' (Roman numeral).
'sort' anagrammed gives 'tors'.
'tors'+'i'='TORSI'

(Another definition for torsi that I've seen is " Rare parts of statues".)

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