Real cute with a thin shape (9)
I believe the answer is:
authentic
'real' is the definition.
(thesaurus)
'cute with a thin shape' is the wordplay.
'with' means one lot of letters go next to another.
'shape' indicates an anagram.
'a'+'thin'='athin'
'cute' put after 'athin' is 'athincute'.
'athincute' is an anagram of 'AUTHENTIC'.
(Other definitions for authentic that I've seen before include "Real, genuine" , "Genuine, not a copy" , "reliable" , "trustworthy" , "Ian, the cut is genuine" .)