Someone who does not appear (show up) for an appointment of any kind is a no-show.

It's short for "not showing up," which means not attending. So, for example: "We expected him to come to the party, but he was a no-show." Notice that we use the article "a" before "no-show," because this is a noun, not a verb (the verb form is "did not show").

The event that somebody tdid not show up when expected, for a match, for a travel, for whatever.