In buff, nether regions one displays? (6)
I believe the answer is:
nudist
'in buff nether regions one displays?' is the definition.
I can't judge whether this definition defines the answer.
'in buff nether regions' is the wordplay.
'in' is an insertion indicator.
'buff' becomes 'nut' (both can mean an enthusiast or fan).
'nether regions' becomes 'dis' (Roman name for the underworld).
'nut' placed around 'dis' is 'NUDIST'.
(Other definitions for nudist that I've seen before include "One going unclothed" , "one economising on clothes" , "Person who discards clothes out of conviction" , "one whose barely seen" , "I want to be 12 [NAKED]" .)