Plumbism refers to lead poisoning, which affects the health of children, especially neurologically. However, the antonyms for this term which would indicate the opposite, would be good health or robustness. Furthermore, the word "neurologic" pertains to the nervous system, its structure, and its functioning, thus its antonyms could be terms such as "unaffected" or "unperturbed". Lastly, "childhood" refers to the period of human life before adulthood, so the antonyms of this could be "adulthood" or "maturity". In conclusion, the antonyms for the phrase "plumbism neurologic childhood" would be robustness, unaffected, perturbed, adulthood, and maturity.