Paternalism
Paternalism (or parentalism) is behavior by an organization or state which limits some person or group's liberty or autonomy for what is presumed to be that person's or group's own good. Paternalism can also imply that the behavior is against or regardless of the will of a person, or also that the behavior expresses an attitude of superiority.
The word paternalism is from the Greek pater (πάτηρ, πατέρας) for father, though paternalism should be distinguished from patriarchy. Some, such as John Stuart Mill, think paternalism to be appropriate towards children: "It is, perhaps, hardly necessary to say that this doctrine is meant to apply only to human beings in the maturity of their faculties. We are not speaking of children, or of young persons below the age which the law may fix as that of manhood or womanhood." Paternalism towards adults is sometimes thought to treat them as if they were children.
Soft and hard paternalism
The terms soft and hard are used in two quite different senses in this context. Philosophers, following Joel Feinberg's influential book Harm to Self (1986), usually use "soft paternalism" for paternalism towards a person whose action or choice is insufficiently voluntary to be genuinely his or hers. Hard paternalism in this usage means paternalism towards a person whose action or choice is sufficiently voluntary to be genuinely his or hers. Soft paternalism in this usage may also refer to interference with a person aimed to establish whether or not his or her action or choice is sufficiently voluntary. In contrast, economists and lawyers usually use "soft paternalism" for mild paternalism, that is paternalism that is not coercive, or not very "heavy-handed". For example, libertarian paternalism is soft paternalism in this sense. Hard paternalism in this usage is coercive paternalism.