The antonyms for the phrase "most giving" largely include words that imply withholding, taking, or selfishness. Examples of antonyms for "most giving" include ungenerous, selfish, uncaring, mean, and stingy. Other antonyms like greedy, self-centered, and hoarding suggest someone who is more focused on personal gain than helping others. A person who is uncharitable or unsympathetic is also unlikely to be described as "most giving." While there may be various reasons why someone is not inclined to be generous, such as financial constraints, lack of empathy, or mistrust, it's often considered a desirable trait to be warm, open-hearted, and giving.