For me it’s heuristic and hermeneutic.
the second one should be easy because of it’s spelling:
“The word hermeneutics is said to have had its origin in the name Hermes, the Greek god who served as messenger for the gods, transmitting and interpreting their communications to their fortunate, or often unfortunate, recipients.”
The first word is a lot harder to deal with but I can make a silly way of remembering it phonetically. “Hi ya wrist, meet rule of thumb”
Can’t think of any words offhand but I know their out there. Personally, I want to kick someone’s ass for using rarely used words in place of something common like “rule of thumb”.
Desultory. I can NOT keep in my mind what it means. I can’t even remember how it’s supposed to be pronounced – is it deh-SUL-tory? DEH-sul-tory? Something else? I can’t remember how many times I’ve looked that damned word up.
Fungible. I’ve looked it up so many times and still can’t get the meaning to stick.
Shibboleth - possibly because it’s a word that I’ve never actually used in conversation (although I’d like to).
Sententious. I can’t tell you how many times I’ve looked it up. For some reason I seem to get it confused with mendacious.
I always get teleology and eschatology confused. They look nothing alike of course, but I first came across both words in the same chapter in a book about Celtic mythology and I made the mistake of looking them up at the same time.
I know what it means, but every time I see it in a novel, I think it is something different.
That would mean the opposite of plussed, I suppose, not that that helps. I still can’t remember its meaning between encounters.
“He was nonplussed.” Hmmm. That means no one has plussed him yet, I guess. Probably been months since he had a good plussing. I know the feeling. Or wait, didn’t I read somewhere that you’re supposed to pluss once a day, before bed? Well then, he has no one to blame but himself.
My dictionary here actually gives two incompatible definitions for the word, so maybe I’m not alone: apparently it means either (1) surprised and confused, or (2) unperturbed. The first meaning is the standard, but the second probably comes from people like me who can’t remember it, but decide to wing it anyway.
What finally cemented that one for me was the West Wing episode that revolved around it.
Tautology. I can’t remember how many times I’ve looked it up, but for some reason the definition never sticks.
Perfidy - I think I might be getting it now that I’ve read a children’s book The Tale of Despereaux.