Being in serious trouble is a difficult situation to navigate. However, there are several synonyms that can be used to describe this predicament. One option is "in dire straits", which emphasizes the severity of the problem. Another synonym is "in hot water", which suggests that the individual is facing negative consequences for their actions. Additionally, "in deep trouble" can be used to describe a serious problem that is challenging to resolve. Lastly, "in a tight spot" implies that the individual is struggling and needs assistance to overcome their difficulties. While each synonym has a slightly different connotation, all convey the seriousness of the situation at hand.