al·le·giance /əˈliːdʒəns/ ●○○ noun [countableC, uncountableU] FAITHFULloyalty to a leader, country, belief etc 〔对领袖、国家、信念等的〕忠诚,效忠allegiance to You owe allegiance (=have a duty to give allegiance) to your king. 你必须效忠国王。
swear/pledge allegiance I pledge allegiance to the flag of the United States of America. 我向美国国旗宣誓效忠。
an oath of allegiance 效忠宣誓
switch/transfer allegiance (=start to support a different person, group etc) 改变拥戴对象
The people here have strong political allegiances. 这里的民众政治忠诚度很高。