If you want to know what competitive programming is, you won’t find the answer in a standard dictionary. Instead, you could look on Wikipedia. It’s not the most hospitable site for competitive programming content, and the main competitive programming article is rudimentary at best. But at least there’s an article, and it hasn’t been deleted (yet).
Alternatively, you could browse the 23 or so answers to the Quora question What is competitive programming? (my answer).
I also wrote a blog post a few years ago that answers the question in a different way: What is Competitive Programming?
Why is this post so short? Find the answer, and links to a blog table of contents, at A Summer 2019 Experiment.