The term "most cavillous" is not widely used in contemporary language, making it challenging to find antonyms directly related to it. However, looking at the meaning of the word "cavillous," which means "inclined to cavil or find fault," one can deduce some probable antonyms to the phrase "most cavillous." For instance, "unbiased," "unprejudiced," "open-minded," "fair," and "impartial" could all be suggested antonyms to this term. These words denote a personality that is accommodating, honest, and receptive, unlike the constantly criticizing and fault-finding attributes of someone described as "most cavillous.