The phrase "showed one's age" refers to a person or thing appearing outdated or no longer relevant. There are several synonyms that can be used to convey this sense, such as "dated," "obsolete," "old-fashioned," "antiquated," "passe," and "outmoded." These words describe something that is no longer fashionable or has fallen out of use, and may imply a lack of modernity or relevance. Using these synonyms in place of "showed one's age" can help convey the same meaning in a more concise or impactful way, depending on the context.