Circus performer close up (4)
I believe the answer is:
seal
I believe this clue is a double definition.
'circus performer' is the first definition.
(I've seen this in another clue)
'close up' is the second definition.
(I've seen this in another clue)
(Other definitions for seal that I've seen before include "relative of the walrus" , "Stick down" , "Aquatic mammal - close securely" , "Make airtight" , "Signet" .)