Final answer:
Coercion is the term used to describe the act of using one's authority or weakness to secure consent to a contract.
Step-by-step explanation:
The term used to describe the act of using one's authority or weakness to secure consent to a contract is coercion.
Coercion refers to the use of threats, force, or other forms of pressure to manipulate someone into agreeing to a contract against their will. It undermines a person's autonomy and makes informed consent and the exercise of agency impossible.
For example, if someone in a position of power uses their authority to force someone to sign a contract by threatening to take away their job or harm them in some way, that is considered coercion.