Nolo's Plain-English Law Dictionary

Undue Influence

Improper influence over someone who is making financial decisions, commonly about making gifts,leaving property at death, or signing a contract.Typically, it occurs when the person is susceptible to pressure because of illness or emotional state, and is taken advantage of by someone he or she depends on for guidance--for example, a lawyer or family member.Undue influence is a ground for challenging the validity of a will or other document in court. (See also: will contest)