'Paradigm'. It gets used a lot and I'm forever having to look it up to be sure what the person means. I just had to look it up right now and five definitions in I found 'model' was a synonym. If they'd just written, "...this is the general model [of the thing]..." I'd have had not trouble.
'Didactic'. Never a clue. No matter how many times I look it up it never sticks in my head. I guess it's just one of those words I never needed to use.
There's another one political types use a lot that I don't like. I can't remember it now (predictably).