Isolation: If you're thinking of community as a sense of belonging and connection, then isolation would be the antonym.
Individualism: If you're considering community as a collective group, then individualism would be the antonym, emphasizing individual self-reliance and separation.
Division: If you're thinking of community as a unified whole, then division would be the antonym, representing separation and conflict.
Alienation: If you're thinking of community as a feeling of belonging, then alienation would be the antonym, referring to a feeling of estrangement or separation.
Anonymity: If you're thinking of community as a place where people know each other, then anonymity would be the antonym, referring to a lack of identity and connection.
The best antonym will depend on the specific context in which you are using the word "community."