Some people may use "axed" in correctly. But it generally means the story got cancelled by the publisher. Think of the publishing company beheading/executing a story with an axe.
For clarification, it got cancelled. If you ever need confirmation, this sort of stuff is best to check on sites like bakaupdates (mangaupdates). These are sites that give you the official information of the series. Baka updates in particular is good at everything except Genre and Categories (since those are sometimes subjective).
WHAT TO DO:
Basically, if you google "The Demon Prince goes to the Academy baka" you should see the following link: https://www.mangaupdates.com/series/kcvqli9/demon-king-of-the-royal-class
In that page, you need to look for "Status in Country of Origin" and that will tell you whether the story is ongoing/completed/on hiatus/cancelled (by the publisher)/discontinued (by the author; for instance when the author dies). For this particular story, the official status is cancelled.
I suggest keeping the website in mind. It'll help you with any similar inquiry you have. I've been using baka updates for over 15 years.

What do you guys mean by axed?!?