What is the term for a person in a special relationship that causes another's action to be contrary to their free will?

The term that refers to a situation where a person, due to a special relationship, causes another individual to act contrary to their free will is known as undue influence. This concept typically arises in contexts such as estate planning or making decisions about legal matters, where one party may have a significant amount of power or trust over another. For example, this can occur when a caregiver exerts influence over an elderly person to change their will.

Undue influence is characterized by a relationship where one party takes advantage of their position to persuade the other party into making decisions they might not have made independently. The relationship often has an inherent imbalance of power, such as that between a trustee and a beneficiary, a caregiver and a dependent, or even a close family member and an elderly individual.

In contrast, concepts like exploitation and manipulation, while they suggest a misuse of power or trust, do not specifically embody the legally defined circumstances of undue influence, which necessitates that the influence is exerted through a particular type of relationship. Coercion, on the other hand, involves threats or intimidation to compel someone to act against their will, which distinctly differs from the subtler, more relational aspect of undue influence.