off pitch as just singing the wrong notes - e.g., notes that were neither the melody nor a reasonable harmony

That also describes the woman I mention. It says more about me than her that I'm trying to describe her note errors in terms of what she was aiming at. Before her lessons, you'd certainly have had NO idea what she was aiming at by listening to her! Who, coincidentally, is now also dead, heart attack in her case.

I have another friend who can sort of sing in tune if the music is in exactly the right key (I forget what key it is) but it's the only key she can sing in no matter the key of the music she's trying to sing along with. Ouch. But lots of enthusiasm!