Most half-grown is a phrase used to describe something or someone who is partially developed or immature. Antonyms for this term include fully developed, mature, grown-up, and adult. These words imply completion, full functioning, and experience. A person who is fully developed has reached their potential physically and mentally, while an adult has gained experience and learned how to navigate complex situations. Mature suggests a level of responsibility and wisdom that comes with age, while grown-up implies the ability to make decisions independently. These words are often used to describe people, but they can also be used to describe objects or concepts, such as a fully developed idea or a mature business plan.