The word "not measurably" suggests that something cannot be quantified or measured accurately. Therefore, its antonyms typically represent ideas that can be measured or observed with precision. Some antonyms for "not measurably" include, "quantifiable," "definite," "measurable," "observable," "tangible," and "evident". These words refer to the ability to observe, detect or understand something in detail or with a degree of accuracy. On the other hand, the antonyms of "not measurably" are often used to describe concrete concepts, scientific phenomena, or physical properties that can be quantified or experienced with the senses.