The word "re-joined" means to connect or unite again. The antonyms for "re-joined" are words that refer to disconnection or separation. Some antonyms for "re-joined" include "detached," "separated," "divorced," "divided," and "segregated." These words denote a state of disunity, which is the opposite of the meaning of "re-joined." In various circumstances, these antonyms, i.e., disassociated, or disconnected, may be applicable. The antonyms of "re-joined" can be used to express different meanings such as detaching oneself from a situation, separating oneself from others or splitting up an entity. Knowing these antonyms can add depth and variety to one's vocabulary, especially when used in writing.