Face in Vogue (7)
I believe the answer is:
italics
'face in vogue' is the definition.
Although both the answer and 'vogue' are nouns, they are not in the same form of the noun.
'face in vogue' is the wordplay.
'face' becomes 'italic' (italic is a kind of face).
'in vogue' becomes 's' (I can't explain this - if you can you should believe this answer much more).
'italic'+'s'='ITALICS'
Can you help me to learn more?
(Other definitions for italics that I've seen before include "Sloping characters" , "Sloping typefaces" , "Sloping font" , "They emphasise" , "Letters slanted to the right" .)