サポーター
さぽーたー
noun
supporter, brace
1.
supporter, fan
A person who actively supports a sports team, cause, or person.
2.
support brace, athletic support
A band or wrap worn to support and protect a joint or muscle during physical activity.
Common collocations
Sense 1:
Sense 2:
Usage
In the context of sports fandom (sense 1), サポーター is the standard term for soccer/football fans in Japan, equivalent to "supporter" in British English. For other sports, ファン is more common.