Focused, coin placed on roulette choice (7)
I believe the answer is:
centred
'focused' is the definition.
(synonyms)
'coin placed on roulette choice' is the wordplay.
'coin' becomes 'cent' (cent is a kind of coin).
'placed on' means one lot of letters go next to another (in a down clue, some letters go on top of others).
'roulette choice' becomes 'red' (I've seen this in another clue).
'cent'+'red'='CENTRED'
(Other definitions for centred that I've seen before include "Placed in the middle" , "Moved to the middle" , "half way across?" , "Positioned centrally" .)