One cast as a trapper? (3)
I believe the answer is:
net
'trapper?' is the definition.
(something which traps)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for net that I've seen before include "Fine open-weave fabric" , "Meshed trap" , "Mesh or web" , "It's see-through" , "Snare or trap" .)