An item that is not cooked to the guest's satisfaction and must be placed back on the grill is known as:

The term that accurately describes an item not cooked to the guest's satisfaction that needs to be placed back on the grill is “refire.” This terminology is commonly used in the culinary industry to indicate that a dish needs to be cooked again to meet the desired standards of the guest. A refire typically means the item is sent back to the kitchen for additional cooking, allowing for adjustments in doneness or temperature to ensure it aligns with the guest's preferences.

In contrast, "recook" might imply a similar action but is not as widely recognized in this specific context, while "upcook" and "redo" are not standard culinary terms for addressing items that need to be re-cooked for guest satisfaction. Recognizing the standard terminology helps in maintaining effective communication in a kitchen environment, particularly when addressing concerns related to food preparation and presentation.