Outing; stumble (4)
I believe the answer is:
trip
This clue is a double definition.
'outing' is the first definition.
(I've seen this before)
'stumble' is the second definition.
(I know that stumble can be written as trip)
(Other definitions for trip that I've seen before include "Accidental misstep" , "Set off for" , "Journey for some purpose" , "A short journey - stumble on it" , "Outing; stumble" .)