How to disable a specific key in a specific app

I am using an app where I need to often type a specific key, but often end up hitting another key that I don't need to be using at all. It is very annoying. Is there a way to disable this useless key just in the specific app? (disable meaning when I press the key, absolutely nothing happens).

In my settings, I can add the key sequence of just that one key in the trigger, but then "No action" doesn't seem to be a valid action that BetterTouchTool can accept for the key to do. I can't seem to find a random action that the key can do that doesn't have an affect, they seem to all "do" things.

There must be a way to do this, I just don't know how. Any help would be appreciated.

Is your key a simple main key, like a letter or function key? Or a modifier key?

You could try "Delay next action by 0.00 seconds" and no other action.

If you are pressing both a modifier key and a key you want to block, it won't disable the pair, so you'd have to add some other blocker triggers for Shift + (yourkey), Cmd + (yourkey), etc.