@Riot League balance terms that need clarification.

Hello Everyone, I have been playing this game for a while now but I am constantly confused on what some terms mean and why they are deemed as strong language and more than reasonable for something to be changed. For example, if something is deemed TOXIC, or UNHEALTHY, then it mush be changed. But the terms TOXIC or UNHEALTHY to the game are never fully explained. They seem to be blanket terms used to then buff or in most times nerf a champion from orbit. Every time I see the term they are used in a almost hypocritical fashion. Example, X character shouldn't have a stun like this but the trade off is damage but they now cant defend against the many highly mobile champs. Then we see a character that has that and more in spades and can hop over walls, many flashes, hard and soft CC, shields, high damage, etc... (sadly that is a number of champions) and its considered healthy to the game. I am lost a bit because if an immobile mage has a decent stun its considered toxic but if another champion has all this and more its healthy. I don't know what these terms mean anymore considering that they are not constant across the game and champion design.

I am not here to bash and I hope that this is not confused for that. But I am still very confused on what these terms mean and are they a static terms that have a definite meaning, and if so what do they mean because they are never used consistently to be commonly understood when they are communicated. Thank you for reading.