Runted means stunted, undersized, or dwarfish. Antonyms for runted could be taller, larger, or bigger. Instead of runted, the opposite could be grown, expanded, or flourished. Some related antonyms may be thriving, flourishing, or booming. These words suggest that something is healthy or prosperous. Runted has a negative connotation, which could be counteracted with positive antonyms like healthy, thriving, or vigorous. In summary, runted has several antonyms that could emphasize its opposite, emphasizing positive growth, and a healthy thriving state.