General Unwelcomeness:
* Give the cold shoulder: This implies deliberate ignoring and lack of warmth.
* Make someone feel out of place: This emphasizes a sense of not belonging or fitting in.
* Show someone the door: This suggests a direct dismissal or request to leave.
Passive-Aggressive Unwelcomeness:
* Give someone the silent treatment: This involves deliberately ignoring or refusing to communicate with someone.
* Make someone feel like a fifth wheel: This implies that the person is not needed or wanted in a group.
* Act like someone isn't even there: This shows blatant disregard and indifference.
Other Options:
* Make someone feel like an outsider: This emphasizes the feeling of being excluded or not part of the group.
* Make someone feel unwelcome: This is a direct and straightforward way of saying it.
The best idiom to use depends on the specific context and the tone you want to convey.