The antonyms for the word "more approximative" include precise, accurate, specific, definite, exact, and true. These words are opposite in meaning to the word "approximative," which suggests a close proximity to but not an exactness of a measurement or calculation. Precision refers to exactness, while accuracy means correctness. Specific means clear or precise, whereas definite means exact or fixed. Exact is another word for precise, while true indicates authenticity or exactness. These antonyms provide alternatives to describing measurements or calculations with more certainty and accuracy.