"Predecided" is a word used to describe a situation that has already been determined or decided upon before any action has been taken. Some synonyms for this word include predetermined, preplanned, prearranged, preconceived, and established. These words all convey the idea that something was decided in advance and may have limited flexibility or room for negotiation in the future. Other related words may include prescribed, preordained, or mapped out. It is important to consider the context in which these words are used, as they can have slightly different connotations and implications depending on the situation. Nonetheless, all of these synonyms for "predecided" emphasize the sense of already being determined.