Outspoken Arab leader causing upset (5)
I believe the answer is:
shake
'upset' is the definition.
(I've seen this before)
'outspoken arab leader' is the wordplay.
'outspoken' shows a homophone (sound like) (as the word might be spoken).
'arab leader' becomes 'sheik' (I've seen this before).
'sheik' is a homophone of 'SHAKE'.
'causing' is the link.
(Other definitions for shake that I've seen before include "Tremble, vibrate" , "Shiver" , "Upset" , "Tremble, quake" , "damaging blow" .)