What term describes a contract that is not formal?

The term that describes a contract that is not formal is a simple contract. Simple contracts are often characterized by their lack of extensive formalities or specific requirements for execution, such as signatures or written documentation. They are generally enforceable as long as there is an offer, acceptance, and consideration involved, which indicates a mutual agreement between the parties.

In contrast, an implied contract is formed by the behavior or actions of the parties involved, rather than through explicit agreements. A written contract explicitly outlines the terms in written form, which adds a layer of formalism and legal clarity that a simple contract does not necessarily require. An oral contract, while it may not be formalized in writing, still requires clear communication and agreement between parties but is distinct from the general concept of a simple contract. Therefore, the focus on the lack of formal requirements in a simple contract makes it the correct answer.