The word "under-studies" typically refers to the people who serve as replacements or stand-ins for actors in a production, movie or theatre. In contrast, antonyms for "under-studies" would include "stars", "leads" or "principal actors" who take center-stage and receive top-billing in productions. Other antonyms for "under-studies" might include "protagonists", "headliners", or "main players". It's worth noting that while under-studies may have important roles, they are ultimately secondary to the main actors, and often take on their roles only when needed. Overall, the antonyms for "under-studies" entail those who have a higher level of importance and presence within a performance or show.