Direct Opposites:
* Rejector: This implies actively refusing someone or something.
* Ignorer: This implies completely dismissing someone or something.
* Repeller: This implies actively pushing someone or something away.
More Subtle Antonyms:
* Dismissal: This could refer to the act of dismissing someone, or a general lack of welcoming or acknowledgement.
* Discourager: This implies discouraging someone from entering or participating.
* Deterrer: This implies making someone hesitant or unwilling to approach.
Other Options:
* Secretive: This describes someone who doesn't readily welcome people in.
* Unfriendly: This describes someone who isn't welcoming or hospitable.
To choose the best antonym, consider the context of the word "greeter" in your sentence.