Tents on mountain maybe being affected (4,4)
I believe the answer is:
high camp
'being affected' is the definition.
(I've seen this before)
'tents on mountain' is the wordplay.
'tents' becomes 'camp'.
'on' means one lot of letters go next to another.
'mountain' becomes 'high' (I am not sure about this - if you are sure you should believe this answer much more).
'camp' after 'high' is 'HIGH CAMP'.
'maybe' is the link.
Can you help me to learn more?
(Other definitions for high camp that I've seen before include "Deliberate extravagance" , "tents on Everest?" , "mountaineer's temporary sleeping quarters?" , "affected in the extreme" , "Outrageous extravagance" .)