I also play with the OP and "with" in our casual games. My view is this, and I think is honestly the best definition of "cheap." Before I start, mjsdawg, you are a huge f@g for bringing this dumb sh*t online looking for sympathy and "proof."
For something be cheap in Smash, it must do something that takes the mindgames out of the equation. D3's chaingrab and basically any infinite is cheap because it is impossible to counter with mindgames. Period. The IC's freeze glitch in Melee was cheap because it took the mindgames out of the game when it was use.
There has to be a distinction between "cheapness" and "overpowered." Take Fox's shine in Melee for example. It was one of the few moves in the game that could kill at very low percents and was hard to punish. Relatively speaking, it was one of the best moves in the game and arguably was "overpowered."One can make the case for other relatively strong moves.
Other things mentioned like Lucario's priority, D-air, Wolf's F-smash, etc. aren't cheap, but I suppose you could label them "overpowered" or just "good moves." You, as the opponent, have the option to attempt to use mindgames on your opponent and punish those consequences of the failed move. Characters are going to have good and bad attributes about them. And in general, characters that have the most and best good, but not cheap moves, should be the highest on the tier list. There's no shame in using these good moves, because you are simply just gimping your potential by not using the best moves. A Fox in Melee that didn't shine or a Falco that didn't ShL would not be playing the character to the potential.
You have to draw a line though, and that line comes when doing something so mindgames can NEVER change the outcome of the combo doesn't feel right. Mindgames are probably the biggest determining factor between players, not technical skill (although in most cases, a player with better technical skill will also have better mindgames). If you take mindgames out of the game by chaingrabbing, you're basically reducing the game to a simple rendition of button-pressing patterns. That's not Smash, nor is it fun.
There's a definite distinction between a move/combo that is cheap, and one that is good. And in our friendlies where literally nothing is on the line but sitting out for one match, there's no need to cross that line...ever.