They show one's out of undies, perhaps (5)

I believe the answer is:
nudes
'they' is the definition.
Both the definition and answer are plural nouns.
Perhaps there's a link between them I don't understand?
'one's out of undies perhaps' is the wordplay.
'one' becomes 'i' (Roman numeral).
'out of' indicates named letters should be taken away ('out of' can mean no longer having).
'perhaps' indicates anagramming the letters.
'undies' with 'i' taken away is 'undes'.
'undes' is an anagram of 'NUDES'.
'show' is the link.
Can you help me to learn more?
(Other definitions for nudes that I've seen before include "They wear nothing" , "page-three features?" , "Naked figures in paintings" , "Revealing paintings?" , "Dunes (anag.)" .)
