Be clearly visible, as in The print doesn't show up against this dark background. [Late 1800s]
Put in an appearance, arrive, as in I wonder if he'll show up at all. [Late 1800s]
Expose or reveal the true character of, as in This failure showed up their efforts as a waste of time. [Early 1800s]
Also, show someone up. Surpass someone in ability, outdo someone, as in John's high score on that math test really showed up the rest of the class. [Colloquial; first half of 1900s]
Dictionary.com presents 366 FAQs, incorporating some of the frequently asked questions from the past with newer queries.