The term 'passage out' can be described using a range of synonyms depending on the context. For instance, in the case of a route, it can be referred to as an exit, an escape route, or a way out. In literature, 'passage out' could be interpreted as a reference to a written segment or a quote, in which case, it could be substituted with phrases such as an excerpt, a quote, or a citation. Additionally, if 'passage out' is meant in the context of an action (as in, leaving a place), synonyms could include exiting, departing, evacuating, or fleeing. Ultimately, the appropriate synonym will vary depending on the situation at hand.