More conserving is a term used to refer to the practice of using fewer resources or preserving them efficiently. The antonyms for this phrase, on the other hand, include wasteful, extravagant, and lavish.
Being wasteful means using resources without any regard for their longevity or availability. Extravagant refers to the act of spending more than what is necessary or required. Lastly, lavish describes someone who enjoys excessive spending or consumption without any concern for the consequences it can bring.
In summary, while more conserving embodies the efficient and mindful use of resources, its antonyms of wasteful, extravagant, and lavish are the opposite, and they typically lead to depletion, damage or exhaustion of resources.