A more thorough explanation:

An unenforceable contract is a type of contract that cannot be legally enforced in court. This means that if one party fails to fulfill their obligations under the contract, the other party cannot sue them for breach of contract.

Let's say that John and Jane enter into a contract where John agrees to sell Jane his car for $5,000. However, the contract is not in writing, which is required by law for contracts involving the sale of goods over $500. In this case, the contract is unenforceable because it does not meet the legal requirements for a valid contract.

Another example of an unenforceable contract is a contract that is based on illegal activities. For instance, if two parties enter into a contract to sell illegal drugs, the contract is unenforceable because it is against the law.

These examples illustrate the definition of an unenforceable contract because they show situations where a contract cannot be legally enforced due to a failure to meet legal requirements or because it is based on illegal activities.