PSA: There is a difference between Overpowered and Broken.

Overpowered is when something is fair to play against like gp barrels for example but have such a high amount of power that it's statistically overbearing for people to play against and needs raw number changes.

Broken is something that literally is well, unfair with 0 counterplay. Something such as poppy ult which is something you can't outplay or have any sort of action that makes you beat the skill which makes the experience facing it unfair.

Now that doesn't mean that broken perceived champs are nerf worthy when their whole kit can fit the "unfair" category or else we would see to name a few. But why you may ask? Well typically when champs fit the broken category they have a 1 dimentional playstyle that can be easily countered by items or champions that counter them walk all over them because if they have something that can outplay their kit, since their kit all has 1 goal with similar abilitys doing the same job like per say then they can get dumpstered moreso than champs with more flexible kits that have options which is now termed as "overloaded" by the comunity, BUT in exchange for trading what would be a "broken" champ which is entirely sink or swim based on how well their kit is useable in the meta, to what would then be seen as a "overpowered" kit when then number changes would be able to solve the champion much more easier rather than taking raw power out of their kit to try and add utility to it to make them more flexible.

Changes like these would be ones such as bear to get the molten shield so it would have more impact in terms of its pet mechanics rather than a GG! button to roflstomp people with at the cost of her molten shield getting -10 armor/mr at all ranks making her kit have less raw power to make it more dynamic.

Hope it clears this up when trying to find the terminology to describe champions you find needing nerfs or ways to buff their kit and wanting to be more decisive in your wording.