Concentrated on coin colour (7)
I believe the answer is:
centred
'concentrated' is the definition.
(similar in meaning)
'on coin colour' is the wordplay.
'on' is a charade indicator (letters next to each other).
'coin' becomes 'cent' (cent is a kind of coin).
'colour' becomes 'red' (red is a kind of colour).
'cent'+'red' is 'CENTRED'.
(Other definitions for centred that I've seen before include "Placed in the middle" , "half way across?" , "Positioned centrally" , "Moved to the middle" .)