A political leader's 'friend' creating outrage (5)
I believe the answer is:
appal
'outrage' is the definition.
('appal' can be a synonym of 'outrage')
'a political leader's friend' is the wordplay.
'leader' indicates taking the first letters.
'friend' becomes 'pal' (pal is a kind of friend).
The first letter of 'political' is 'p'.
'a'+'p'+'pal'='APPAL'
'creating' is the link.
(Other definitions for appal that I've seen before include "Disgust" , "Put at rest (suspicion)" , "Greatly dismay" , "Shock, horrify" , "Petrify" .)