(law) Estrangement or loss of affection between two people who have a claim on each other's affections (such as two spouses or a parent and child) that is willfully caused by interference from a third party.

(philosophy, general) a person's feeling of disconnection and/or isolation from a group – whether friends, family, or wider society – or another individual due to low degree of integration or common values

plural of coefficient of alienation

(statistics) A numerical measure of the lack of relationship between variables.

A supposed disturbance in which children are obsessively preoccupied with depreciation and/or criticism of a parent.

The abduction of a person by extraterrestrials.

(sometimes offensive) A person who is within the boundaries of a political state without the authorization of the government of that state; a national of another country who has entered or stayed without permission.

plural of resident alien

(US, law) A person born outside the United States who has legally established temporary or permanent residence in the United States, but has not become a United States citizen.

plural of space alien