If a group of people give someone who is going away a send-off, they come together to say goodbye to them. All the people in the buildings came to give me a rousing send-off. a party or other occasion when people meet to say goodbye to someone who is leaving
If a football player is sent off, the referee makes them leave the field during a game, as a punishment for seriously breaking the rules. The 30-year-old Scottish international was sent off for arguing with a linesman. see also sending-off