What does it mean to expel?

To expel means to force someone or something to leave a place or position. This term is often used in contexts like schools or organizations where a person might be removed due to misconduct or failure to follow rules. The emphasis is on the act of removal, indicating a lack of permission or right to stay. In this way, the term carries a strong connotation of authority, as it typically involves a decision made by someone in a position to grant or deny access.

The other choices do not align with the meaning of "expel." For instance, allowing entry suggests welcoming someone in, inviting signifies actively bringing someone in, and retaining implies keeping someone or something in a particular place. None of these alternatives convey the idea of removal that is central to the definition of expelling.