Defects in a Contract:
Contract law distinguishes between contracts that are voidable, unenforceable, illegal, and valid. When a contract is good in substance but suffers from some technical defect, it is considered unenforceable.

Unenforceable Contract:
An unenforceable contract is a valid contract that cannot be enforced due to a technical defect. This means that even though the contract has all the essential elements of a valid contract, there is some issue that prevents it from being enforced by a court.

Common Reasons for Unenforceability:
1. Lack of Proper Form: Contracts must meet certain formal requirements, such as being in writing, signed by the parties, and fulfilling any statutory requirements.
2. Lack of Capacity: If one or both parties lack the legal capacity to enter into a contract, such as being a minor or mentally incapacitated, the contract may be unenforceable.
3. Illegality: If the purpose of the contract is illegal or against public policy, the contract will be considered unenforceable.
4. Mistake or Misrepresentation: If there was a mistake or misrepresentation in the contract that affects its validity, it may be deemed unenforceable.

Consequences of Unenforceability:
When a contract is deemed unenforceable, it means that the parties cannot rely on the courts to enforce the terms of the contract. This can lead to disputes between the parties and may require alternative methods of resolution, such as negotiation or mediation.
In conclusion, a contract that is good in substance but suffers from a technical defect is considered unenforceable due to the inability to meet certain legal requirements or obligations.