Русско-англо-русский юридический словарь

A foreign national is a person who is not a citizen of the host country in which he or she is residing or temporarily sojourning. For example, a foreign national in Canada is someone who is neither a Canadian citizen nor a permanent resident of Canada. However, in the European Union, a foreign national is a third country national, i.e. someone who is not a citizen of any of the member states of the European Union.

According to the U.S. Department of Homeland Security a foreign national is defined simply as "an individual who is a citizen of any country other than the United States." (Wikipedia)

The proportion of foreign nationals increases for professionally qualified clinical staff (14%) and even more so for doctors (26%), prompting the British Medical Association (BMA) to observe that without the contribution of non-British staff, "many NHS services would struggle to provide effective care to their patients". (The Guardian)

In law, an alien is any person (including an organization) who is not a citizen or a national of a specific country, although definitions and terminology differ to some degree depending upon the continent or region. More generally, however, the term "alien" is perceived as synonymous with foreign national. (Wikipedia)

It is illegal for employers to hire aliens not authorized for employment. (Oxford Advanced Learner's Dictionary)