Definitions for "Undocumented immigrant"
a person who comes to settle in a country without the legal permission of its government. The expression "illegal alien" is considered a pejorative.
A person who comes to a country for residence without the required documentation.
an immigrant with no documentation on him, which may or may not make him an illegal immigrant depending on the circumstances
Keywords:  citizen, potential, actual
a POTENTIAL US citizen, not an actual US citizen