Definition - What does Undue Influence mean?
Undue influence is when a person expresses an opinion or chooses a specific action based on being told to do so by another person who has control over the person committing the act or opinion. The control can be physical, emotional, or anything that deprives one person from their own judgment in lieu of following the objectives of someone else that the person feels they must comply with. Typical relationships that see undue influence being used are husband and wife, doctor and patient, or attorney and client.
Justipedia explains Undue Influence
If a situation is adjudged to have been affected by undue influence, it will be deemed invalid. This is why contracts made between husband and wife are usually considered invalid at the point where they disagree because it is assumed that there will not be fair and equitable distribution and that one person will try to dominate the situation. This is also why guardians can be appointed by the court in cases of incapacitated persons to ensure that their finances are kept sound and that they are not taken advantage of by another person due to ther inability to protect themselves physically or emotionally.