1 to force sb to leave a country, school, club, etc 勒令离开(国家、学校、俱乐部等);驱逐;开除:
The government has expelled all foreign journalists.政府驱逐了所有外国记者。The boy was expelled from school for smoking.该男童因吸烟而被学校开除。
2 to send sth out by force 排出:
to expel air from the lungs从肺里呼出空气☞noun expulsion 名词为 expulsion