Bunker some go back into (4)
I believe the answer is:
trap
'bunker' is the definition.
(I know that bunker can be written as trap)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for trap that I've seen before include "Lure, snare" , "Cakehole (slang)" , "Confine" , "mug" , "Light carriage - it's sometimes sprung!" .)