invader
noun /ɪnˈveɪdə(r)/
  /ɪnˈveɪdər/
 - 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。 
 
- a foreign invader