Parental Alienation (abbreviated as PAS) is a term coined by child psychiatrist Richard A. Gardner, and introduced in his 1985 paper 1), "to describe a suite of distinctive behaviors consistently shown by children who have been psychologically manipulated into showing unwarranted fear, disrespect or hostility towards a parent and/or other family members - typically, by the other parent and during child custody disputes. An early proponent of parental alienation syndrome argued that parental alienation involves a focus on the parent, while parental alienation syndrome also involves hatred and vilification of a targeted parent by the child."
1) RA Gardner: Parental Alienation Syndrome (PAS): Sixteen Years Later. In: Academy Forum. 45, Nr. 1, 2001, S. 10–12.