What are implied terms? 

Most contracts set out their terms expressly, meaning they are written down and agreed by both parties. Implied terms are different. They are obligations or rights that are not written into the contract but are treated as part of it nonetheless, either because the law automatically imposes them or because they are so obviously necessary to make the contract work that both parties would have included them had they thought to. Some implied terms can be excluded by careful drafting; others, particularly those imposed by statute, cannot.