Stumbled on something when on an outing? (7)
I believe the answer is:
tripped
'stumbled' is the definition.
('trip' can be a synonym of 'stumble')
'when on an outing?' is the wordplay.
'when' becomes 'ped' (I am not sure about this - if you are sure you should believe this answer much more).
'on' says to put letters next to each other.
'an outing?' becomes 'trip' (I've seen this before).
'ped' after 'trip' is 'TRIPPED'.
'on something' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for tripped that I've seen before include "Came a cropper" , "Took acid" , "Missed a step, stumbled" .)