The antonyms for the word "most obtaining" would be "least acquiring" or "least obtaining." These words imply a state of having very little or almost nothing, as opposed to having the most. The concept of obtaining refers to obtaining something worthwhile or valuable, such as knowledge or material possessions. Therefore, having the least of these things would be the opposite of having the most. Other antonyms for "most obtaining" could be "least successful," "least productive," or "least prosperous," which all suggest a lack of achievement or success in one's endeavors.