text: what is the difference between an illegal immigrant and a legal immigrant or are they the same?   illegal immigration describes migration across national borders without complying with the legal requirements. some people call those they suspect of illegally immigrating, "illegal immigrants" or "undocumented immigrants".   people who arrive in a legal manner but then outstay their visas (that is the authorized time in the host country), may also have illegal status. the term illegal immigrant is highly contested because some consider it unnecessarily pejorative