Cold when you gain victory with a final score (6)
I believe the answer is:
wintry
'cold' is the definition.
(similar in meaning)
'victory with a final score' is the wordplay.
'victory' becomes 'win' (I've seen this before).
'with' says to put letters next to each other.
'a final score' becomes 'try' (I am not sure about the 'final' bit.).
'win'+'try'='WINTRY'
'when you gain' is the link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for wintry that I've seen before include "anything other than friendly?" , "Glacial" , "characteristic of one season" , "Unfriendly" , "(Of weather) freezing" .)