What does "excellent" "brilliant" and "great" mean in analysis?


Excellent — a move that is very close to the best (usually second-best) to the point that there really isn't much of a difference.
Great — The only move in a position that... (see below)
- Equalizes the game in a formerly losing position
- Gains an advantage in a formerly drawn or equal position
- Wins in an already winning position
- Doesn't lose in a drawn position
- Causes the player's position to go from losing to winning
Brilliant — There are two different definitions:
- Chess.com: a good move that leaves a piece hanging. (No, seriously. That's it.)
- OTB: a surprising and unintuitive move which is extremely difficult to find and often looks like a horrific blunder at first glance, but is actually very strong and typically leaves the opponent in a position where every move loses. It can also rarely be used for unexpected moves in a "losing" position that allow the player to escape with a draw.
Sometimes I play without logging in and then I always see this "analysis". My moves are - if mentioned at all - usually "best", "brilliant", "great" or "good" with the occasional "miss" or "blunder" for good measure.
"Blunder", "miss" and "best" I can understand.
What does "great" mean? Obviously this is not a "best" move, so what is it? A subpar move that doesn't ruin as much as a blunder would?
And what is "brilliant"? Is that a move that achieves something similar to what the "best" move would do, just in a very complicated and unobvious way?
Furthermore, what is "good"? My interpretation (which could be wrong) is that it is a bad move which gives away most but not all of the advantage.
I'd be glad if someone could explain this exactly. Or is this analysis feature (which can't be switched off when not logged in) just the chess.com version of annoying advertisements so that one is nudged to creating an account?