Those illegally in a country are not immigrants. Technically, there is no such thing as an "illegal immigrant". An immigrant is involved with an established and orderly procedure of immigration (entering a country to which one is not native in order to settle there by legal process).
They are not immigrants (the liberal media's favorite), not undocumented immigrants (the PC fan favorite), not undocumented workers (Gloria Allred's favorite), not undocumented Americans (Harry Reid's favorite), not economic immigrants (Big Business favorite), not immigrants without work papers, not people who are working (open borders activist favorite), not migrant workers, not entrants, not day laborers, not the "unbanked" (Bill Clinton and Arnold Schwarzenegger's favorite), not irregular migrants (the U.N.'s favorite) and certainly not "new Americans" the latest term applied by the persistent amnesty zealots. The federal government has defined them as "illegal aliens" since the 1980's and explicitly uses that term in its laws and statutes.