不是外人

不是外人:

Literally means:

not an outsider

Actually means:

An outsider is someone who does not have blood relations with the speaker or someone who does not belong to a community or organization.

This phrase refers to someone who has an intimate relationship with others, or someone who holds the same point of view. It is often used to emphasize a very close relationship.

外人，没有亲友关系的人，或者某个范围或组织以外的人。

不是外人，比喻彼此关系密切，或持有同样观点的人。多用于强调关系的亲密。