The phrase "banging up" typically refers to causing damage or harm to something or someone. Antonyms for this phrase could include repairing, fixing, healing, soothing, calming, or protecting. In essence, anything that offsets the negative effects of "banging up" can be considered an antonym. For example, a doctor may treat and heal a patient's injuries to counteract the harm caused by an accident. Similarly, a mechanic may repair a damaged car to offset the effects of a collision. Using antonyms like these can help to shift the focus from negative actions and consequences to positive outcomes and solutions.