Exults over supporters showing signs of age (5-4)
I believe the answer is:
crows-feet
'signs of age' is the definition.
(lines on the face caused by age)
'exults over supporters' is the wordplay.
'exults' becomes 'crows' (both can mean to brag or behave triumphantly).
'over' is a charade indicator (letters next to each other).
'supporters' becomes 'feet' (both can mean a base or foundation).
'crows'+'feet'='CROWS-FEET'
'showing' is the link.
(Other definitions for crows-feet that I've seen before include "showing signs of ageing" , "What will support some flyers" , "Wrinkles at the outer corner of the eyes" , "Wrinkles beside eyes" , "Wrinkles in skin at side of eyes" .)