What are the opposite words for under-developments?

Antonyms for the word "under-developments" include "matureness," "progress," "improvement," and "advancement." While under-development often connotes a lack of growth or forward movement, these antonyms suggest the opposite - that progress and evolution have been made. A mature society, for instance, has advanced well past its initial stages and is now experiencing growth in a variety of ways. Similarly, an advanced economy may have seen significant improvements in technology, infrastructure, and other areas, leading to a more prosperous and productive society. Ultimately, these antonyms convey the idea of growth, progress, and development, and suggest that anything is possible with hard work and determination.