Skill seen in party piece (3)
I believe the answer is:
art
'skill' is the definition.
(thesaurus)
'in party piece' is the wordplay.
'in' indicates a hidden word.
'ART' can be found hidden inside 'party piece'.
'seen' acts as a link.
(Other definitions for art that I've seen before include "Drawing" , "Paintings etc." , "Eg, paintings, sculpture" , "Skill in a specified thing" , "Works of beauty created by humans" .)