Revealing all the latest: that is expert, outwardly (2,3,4)
I believe the answer is:
in the buff
'revealing all the' is the definition.
I can't tell whether this defines the answer.
'latest that is expert outwardly' is the wordplay.
'latest' becomes 'nth' (I am not sure about this - if you are sure you should believe this answer much more).
'that is' becomes 'ie' (abbreviation for id est, 'that is' in Latin).
'expert' becomes 'buff' (buff can mean an expert or aficionado).
'outwardly' means one lot of letters goes inside another (some letters go on the outside).
'ie'+'buff'='iebuff'
'nth' inserted into 'iebuff' is 'IN THE BUFF'.
Can you help me to learn more?
(Other definitions for in the buff that I've seen before include "concealing nothing?" , "Naked" , "Assuming nothing" .)