The term "most casuistic" implies that there is a level of disingenuousness or insincerity involved in the actions or statements being described. Antonyms for this phrase could include words such as genuine, forthright, sincere, authentic, truthful, honest, and straightforward. These words all convey a sense of openness and honesty, without any hidden agendas or ulterior motives. By contrast, "most casuistic" suggests that there may be a degree of deception involved in the situation, whether intentional or not. By using the right antonyms to describe a situation, we can convey a very different set of values and qualities that may be present in that context.