Well, there's actually multiple versions of Adamantium... So first you'd have to specify which one you're talking about, the Hulk has broken some versions of it, but they basically mean indestructible by any normal means. So not actually completely indestructible, just might as well be unless you have god like power...
https://marvel.fandom.com/wiki/Adamantium
https://www.cbr.com/15-characters-who-broke-adamantium/
However, they can all be destroyed with Antarctic Vibranium, which dissolves all metals...
While Vibranium can absorb energy, it has its limits and can be destroyed if it absorbs too much energy, too quickly...
http://www.marveldirectory.com/miscellaneous/vibranium.htm