Shocked when a page got boring (8)
I believe the answer is:
appalled
'shocked' is the definition.
('appall' can be a synonym of 'shock')
'a page got boring' is the wordplay.
'page' becomes 'p'.
'got boring' becomes 'palled' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'a'+'p'+'palled'='APPALLED'
'when' acts as a link.
Can you help me to learn more?
(Other definitions for appalled that I've seen before include "Deeply shocked, filled with dismay" , "Scandalised" , "Mortified" , "Shocked and horrified" , "Dismayed - aghast" .)