People power unsettled a couple (8)
I believe the answer is:
populace
'people' is the definition.
'power unsettled a couple' is the wordplay.
'power' becomes 'p'.
'unsettled' is an anagram indicator.
'a'+'couple'='acouple'
'acouple' is an anagram of 'opulace'.
'p'+'opulace'='POPULACE'
(Other definitions for populace that I've seen before include "Residents" , "Inhabitants" , "Citizens" , "People generally" , "Common people" .)