The antonyms for the word "overloaded" can be "underloaded" or "underutilized". When something is underutilized, it means that it is not being used to its full potential. It can also mean that there is a lack of resources or demand for it. On the other hand, when something is underloaded, it means that it has a lower capacity or is not fully loaded with its maximum weight or volume. In contrast, when something is overloaded, it means that it has exceeded its capacity or is carrying too much weight or volume. It can lead to potential dangers or issues in functioning properly.