He scored in December game (4)
I believe the answer is:
berg
'he scored' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'in december game' is the wordplay.
'in' says the answer is hidden in the clue.
'BERG' can be found hidden inside 'december game'.
Can you help me to learn more?
(Other definitions for berg that I've seen before include "Lump of ice" , "feature of icy waters" , "trouble at sea" , "He composed" , "Small version of ice mountain" .)