Seen in show, nervous proprietor (5)
I believe the answer is:
owner
'proprietor' is the definition.
(I know that proprietor can be written as owner)
'seen in show nervous' is the wordplay.
'seen in' says the answer is hidden in the clue.
'OWNER' is hidden in the letters of 'show nervous'.
(Other definitions for owner that I've seen before include "Person having property" , "One who possesses" , "Title holder?" , "One that secured" , "landlord" .)