Appalling newspaper discovered during trip (9)
I believe the answer is:
outraging
'appalling' is the definition.
('outrage' can be a synonym of 'appal')
'newspaper discovered during trip' is the wordplay.
I cannot quite see how this works, but
'newspaper' could be 'rag' (informal term for a newspaper) and 'rag' is found within the answer.
'during' could be 'in' (e.g. during February means in February) and 'in' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for outraging that I've seen is " infuriating".)