The antonyms for the word "more surmising" can be certain, definite, conclusive, and definite. While surmising is the act of inferring or guessing, these antonyms indicate firmness, confidence, and certainty. By using such antonyms, you can make your sentence more precise and clearly convey your intended meaning. For instance, "I am more surmising that it may rain" can be rephrased as "I am certain that it will rain," which conveys the speaker's confidence in the predicted weather condition. Using antonyms can add depth and clarity to your language, making it more effective in delivering your message.