Antonyms for the word "most overpermissive" include strict, rigid, stern, unyielding, harsh, inflexible, and austere. These are all words that convey a sense of discipline and structure, rather than the lax and permissive attitude that the original word suggests. While being overpermissive may seem like a positive quality, it can actually lead to chaos and lack of boundaries, especially when it comes to parenting or managing a team. By embodying the opposite qualities of strictness and firmness, we can create an environment of accountability and responsibility that fosters growth and success.