Group of countries anger MEP, disturbed initially (6)
I believe the answer is:
empire
'group of countries' is the definition.
(I've seen this before)
'anger mep disturbed initially' is the wordplay.
'anger' becomes 'ire' ('ire' can be a synonym of 'anger').
'disturbed' is an anagram indicator.
'initially' says to put letters next to each other.
'mep' is an anagram of 'emp'.
'ire' after 'emp' is 'EMPIRE'.
(Other definitions for empire that I've seen before include "Large organisation run from one point" , "Over which 23 down rules" , "Kingdom" , "Large group of states" , "Former British-ruled countries" .)