Fetch out an article that's revealing (6)
I believe the answer is:
baring
'revealing' is the definition.
(thesaurus)
'fetch out an article' is the wordplay.
'fetch' becomes 'bring' (synonyms).
'out' indicates putting letters inside.
'an article' becomes 'a' (indefinite article).
'bring' enclosing 'a' is 'BARING'.
'that's' acts as a link.
(Other definitions for baring that I've seen before include "Stripping or uncovering" , "Exposing" .)