What type of contract requires an explicit agreement between parties to be enforceable?

An express contract is the type of contract that requires an explicit agreement between the parties to be enforceable. In this context, an express contract is one where the terms are clearly stated, whether orally or in writing. This explicit nature means that both parties have a clear understanding and agreement on the obligations they are undertaking. The clarity and explicitness of terms make it easy to identify the parties' intentions and expectations, which is crucial for enforcement in a legal context.

In contrast to express contracts, implied contracts arise from the actions or circumstances of the parties involved rather than through explicit verbal or written agreement. Oral contracts, while they can be express, do not always have written documentation, which may make them more challenging to prove in disputes. A unilateral contract involves only one party making a promise, with the other party's acceptance being indicated through action rather than explicit agreement; thus, it does not require mutual agreement in the same way that express contracts do.