Only GOP could be upset to get this kind of figure (7)
I believe the answer is:
polygon
'upset to get this kind of figure' is the definition.
'polygon' can be an answer for 'kind of figure'. I'm not certain of the remainder of the definition.
'only gop could be' is the wordplay.
'could be' indicates an anagram.
'only'+'gop'='onlygop'
'onlygop' with letters rearranged gives 'POLYGON'.
Can you help me to learn more?
(Other definitions for polygon that I've seen before include "Many-sided plane figure" , "Straight-sided figure" , "shape" , "Plane figure with a number of straight sides" , "Closed plane figure with three or more straight sides" .)