ちじん知人chijin
1.
A person with whom one has a mutual recognition or familiarity, often through social connections but not necessarily a close relationship.
2.
An individual one knows, typically in a casual or informal context, who may not be a close friend but is recognized or acknowledged.
3.
Someone identified through a shared connection or circumstance, indicating a level of acquaintance without implying deep personal ties.
Example:
もし私の家が大邸宅だったら私の誕生日のパーティーには知人をみんな招待するのだが。