an army or a country that enters another country by force in order to take control of it; a soldier fighting in such an army 武装入侵的军队(或国家);侵略者 a foreign invader 外国侵略者 They prepared to repel the invaders. 他们准备赶走侵略军。 - (figurative)
The white blood cells attack cells infected with an invader. 白细胞攻击受到感染的细胞。