Just one dropped round for gambling game (4)
I believe the answer is:
faro
'gambling game' is the definition.
(I've seen this before)
'just one dropped round for' is the wordplay.
'just' becomes 'fair' ('fair' is associated in meaning with 'just').
'one' becomes 'i' (Roman numeral).
'dropped' is a deletion indicator.
'round for' becomes 'o' (I can't explain this - if you can you should give a lot more credence to this answer).
'fair' with 'i' taken out is 'far'.
'far'+'o'='FARO'
Can you help me to learn more?
(Other definitions for faro that I've seen before include "Card game - Algarve port" , "Atlantic port" , "Algarve seaport" , "European port" , "Gambling game - Algarve capital" .)