The word "over-powered" generally implies an excess of power or control. Some possible antonyms for this term might include words such as "under-powered," "weak," or "feeble." Other possible antonyms might include "balanced," "moderate," or "controlled." Ultimately, the choice of antonym will depend on the context in which the word is being used. For example, if someone is describing a powerful machine that is difficult to control, they might use the term "over-powered." Conversely, if they are describing a machine that is difficult to control because it lacks sufficient power, they might use the term "under-powered." Overall, choosing the appropriate antonym is crucial in accurately conveying the desired meaning.