illegal alien
noun [ C ] US uk/ɪˌliː.ɡəl ˈeɪ.li.ən/ us/ɪˌliː.ɡəl ˈeɪ.li.ən/
非法（在其他国家生活或工作）的外国人
someone who lives or works in another country when they do not have the legal right to do this
Note: This term is considered offensive by many people. Use undocumented immigrant or undocumented person instead.
Synonym: illegal immigrant