Outing presumably not a stumble in the dark (3,4)
I believe the answer is:
day trip
'outing' is the definition.
(I've seen this before)
'presumably not a stumble in the dark' is the wordplay.
I cannot quite understand how this works, but
'a' is found in the answer.
'stumble' could be 'trip' (synonyms) and 'trip' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for day trip that I've seen before include "Excursion within 24 hours" , "Outing" , "Pay dirt (anag.)" , "Brief excursion" .)