Coordinated part of shoe (6)
I believe the answer is:
instep
'part of shoe' is the definition.
('instep' is part of 'shoe')
I can't explain the rest of the clue.
(Other definitions for instep that I've seen before include "Set pin in part of foot" , "Arch we stand on" , "downtrodden area" , "Part of foot (how to march!)" , "Sir Jack --, famous English cricketer" .)