Trapeze artist's safeguard (3)
I believe the answer is:
net
'trapeze artist's safeguard' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for net that I've seen before include "Catch -- after all deductions" , "Capture" , "Amount remaining after deductions" , "Mesh; after tax" , "Catch, ensnare" .)