Final answer:
A legally ineffective agreement is termed void, it is unenforceable from the start because of reasons such as illegality or incapacity of the parties involved.
Step-by-step explanation:
An agreement without legal effect is known as void. This means that the agreement has no legal force from the beginning and cannot be enforced by law. Factors that can make an agreement void include illegality, incapacity of parties, and lack of requisite formalities. For example, an agreement to commit a crime is void. This is different from a voidable agreement, which is one that may appear to be valid but can be rejected by one party due to certain issues, such as misrepresentation or coercion.