The antonyms for the phrase "is edge" are numerous and varied. Opposite words for "is" could be "is not," "isn't," or "wasn't," which convey negation or absence. Antonyms for "edge" could be "center," "middle," or "interior," which indicate a lack of boundary or limit. Additionally, "rounded," "soft," or "blunt" could also serve as antonyms for "edge," since they imply a less defined, less sharp shape. In summary, the antonyms for "is edge" emphasize a lack of definition, boundary, or sharpness, and suggest less structure or precision.