There are campaigns discouraging the use of the term "illegal immigrant", generally based on the argument that the act of immigrating illegally does not make the people themselves illegal, but rather they are "people who have immigrated illegally". In the United States, a "Drop the I-Word" campaign was launched in 2010 advocating for the use of terms such as undocumented immigrants or unauthorized immigrants when referring to the foreign nationals who reside in a country illegally.
News associations that have discontinued or discourage the use of the adjective "illegal" to qualify nouns that describe people include the US Associated Press, UK Press Association, European Journalism Observatory, European Journalism Centre, Association of European Journalists, Australian Press Council, and Australian Media, Entertainment and Arts Alliance. Related terms that describe actions are not similarly discouraged by these campaigns. For example, Associated Press continues to use the term "illegal immigration" to describe the action of entering or residing in a country illegally.
In contrast, in some contexts the term "illegal immigrants" is shortened, often pejoratively, to "illegals".
On the other hand, the term undocumented has been cited by The New York Times, as a "term preferred by many immigrants and their advocates, but it has a flavor of euphemism and should be used with caution outside quotation". Newsweek questions the use of the phrase 'undocumented immigrants' as a method of euphemistic framing, namely, "a psychological technique that can influence the perception of social phenomena". Newsweek also suggests that persons who enter a country unlawfully cannot be entirely "undocumented" because they "just lack the certain specific documents for legal residency and employment. Many have driver's licences, debit cards, library cards, and school identifications which are useful documents in specific contexts but not nearly so much for immigration." For example, in the U.S., youths brought into the country illegally are granted access to public K-12 education and benefits regardless of citizenship status, so the youths are documented for educational purposes, and are not entirely undocumented.
A related term, irregular migration, is sometimes used e.g. by the International Organization for Migration, but it describes a somewhat wider concept which also includes illegal emigration.
U.S. immigration laws use the phrase illegal immigrant at least in some contexts. Title 8 of the US Code is the portion of the law that contains laws on citizenship, nationality, and immigration. It defines the legal term Alien as "any person not a citizen or national of the United States". Terminology used in Title 8 includes illegal alien (33 times), unauthorized alien (21 times), undocumented alien (18 times), illegal immigrant (6 times), undocumented person (2 times) and others. An analysis by PolitiFact however concluded that the term "illegal alien" "occurs scarcely, often undefined or part of an introductory title or limited to apply to certain individuals convicted of felonies".
In the United States, while overstaying a visa is a civil violation handled by immigration court, entering (including re-entering) the US without approval from an immigration officer is a crime: specifically a misdemeanor on the first offense. Illegal reentry after deportation is a felony offense. This is the distinction between the larger group referred to as unauthorized immigrants and the smaller subgroup referred to as criminal immigrants.