The antonyms for the word "New Acceptors" could be existing clients, established members, longtime supporters, regular attendees, or loyal customers. These antonyms signify people who have been associated with a particular group, organization, or business for a considerable period of time and have developed a certain level of trust, familiarity, and loyalty. While new acceptors denote a group of people who have recently joined, discovered, or shown interest in something, the antonyms portray those who have a history and a certain level of investment in the said entity. Therefore, having a balance between new acceptors and existing clients can contribute to a stable and thriving entity.