Showed off in football league and spooked Cockney (8)
I believe the answer is:
flaunted
'showed off' is the definition.
('flaunt' can be a synonym of 'show off')
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for flaunted that I've seen before include "Displayed proudly or ostentatiously" , "Waved proudly" , "Displayed ostentatiously or pretentiously" .)