Give one player on national team a penalty (8)
I believe the answer is:
handicap
'a penalty' is the definition.
(thesaurus)
'give one player on national team' is the wordplay.
'give' becomes 'hand' ('hand' can be a synonym of 'give').
'one' becomes 'i' (Roman numeral).
'player on national team' becomes 'cap' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'hand'+'i'+'cap'='HANDICAP'
Can you help me to learn more?
(Other definitions for handicap that I've seen before include "Advantage given to equalise chances of winning" , "Put at a disadvantage" , "Obstacle" , "Impairment" , "Grand National for example" .)