Who is a Refugee? 1951 - UN Convention

Someone who owing to a well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group, or political opinion, is outside the country of their nationality, and is unable to or, owing to such fear, is unwilling to avail him/herself of the protection of that country.

Source: United Nation High Commissioner for Refugees (UNHCR)