Catch bunker (4)
I believe the answer is:
trap
This clue is a double definition.
'catch' is the first definition.
(trapping is a kind of catching)
'bunker' is the second definition.
('trap' can be a synonym of 'bunker')
(Other definitions for trap that I've seen before include "get in net" , "Vehicle" , "Snaring device" , "Control ball" , "Part of a snare" .)