Dictionary.net

A guarantee about the quality of goods or services purchased that is not written down or explicitly spoken. Virtually everything you buy comes with two implied warranties. One for "merchantability" and one for "fitness." The implied warranty of merchantability is an assurance that a new item will work for its specified purpose. The item doesn't have to work wonderfully, and if you use it for something it wasn't designed for, say trimming shrubs with an electric carving knife, the warranty doesn't apply. The implied warranty of fitness applies when you buy an item for a specific purpose. If you notified the seller of your specific needs, the item is guaranteed to meet them. For example, if you buy new tires for your bicycle after telling the store clerk that you plan to use them for mountain cycling and the tires puncture when you pass over a small rock, the tires don't conform to the warranty of fitness.