Pass through without first stopping (4)
I believe the answer is:
visa
'pass' is the definition.
(I've seen this before)
'through without first stopping' is the wordplay.
'through' becomes 'via' (I've seen this before).
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'first stopping' becomes 's' (1st letter of 'stopping').
'via' going around 's' is 'VISA'.
(Other definitions for visa that I've seen before include "It allows the bearer to enter the country issuing it" , "ID" , "Mark on passport" , "Endorsement made in a passport" , "Endorsement allowing bearer to enter country" .)