Everybody leaves superficial exhibition (4)
I believe the answer is:
show
'exhibition' is the definition.
(thesaurus)
'everybody leaves superficial' is the wordplay.
'everybody' becomes 'all' (I've seen this before).
'leaves' indicates named letters should be taken away.
'superficial' becomes 'shallow' ('shallow' can be similar in meaning to 'superficial').
'shallow' with 'all' removed is 'SHOW'.
(Other definitions for show that I've seen before include "Display or exhibition" , "Demonstrate; spectacle" , "charade" , "Demonstrate or reveal" , "Display; prove" .)