The phrase "fact of life" refers to a reality that cannot be changed or avoided. There are several synonyms that can be used to describe this concept, including inevitability, reality, truth, certainty, actuality, and verity. Each of these words represents a different aspect of the idea that some things are just the way they are and cannot be altered. For example, inevitability suggests that something is fated to happen, while reality emphasizes the concrete existence of a situation. Whether discussing the challenges of growing up, the inevitability of death, or the harsh realities of the world, the phrase "fact of life" can be replaced with a variety of other words that capture its essence.