Cooler to attack supporters? (3,4)
I believe the answer is:
fan club
'supporters?' is the definition.
'cooler to attack' is the wordplay.
'cooler' becomes 'fan' (I've seen this in other clues).
'to attack' becomes 'club' (to attack with a club).
'fan'+'club'='FAN CLUB'
(Other definitions for fan club that I've seen before include "Organised supporters' group" , "Admiring band" , "Group of admirers as for pop star" , "Association of ardent followers" , "Fervent admirers" .)