In my writers' group, people occasionally complain that they're not familiar with words I use, such as blunderbuss, limn, and others. Should I dumb my language down, or expect my readers to understand from context or look words up?

Do they really?

Well, tell them that in your experience readers often seem to have adequate vocabularies and don’t need to have stories presented exclusively in words designed for the instant comprehension of fifth graders. You can say that as sharply as you like. I think such a ridiculous complaint deserves a pretty sharp tone.

Today, when everybody has a dictionary in their pocket, it is even more ridiculous to say “Oh no, the poor reader might not know what “limn” means.” If the reader wants to look it up, that will literally take less than five seconds, though the meaning is generally fairly clear from context.

Do not dumb down your vocabulary.

That’s my personal opinion, but I will just note here that my Random House editor did not suggest removing the word “chatoyant” from my fantasy novel that was marketed for MG and younger YA readers. If that editor thought twelve-year-old kids could manage to cope with the word “chatoyant,” I can’t see a lot of room to argue that adult readers can’t cope with “blunderbuss.”

I only ever had ONE copy editor suggest ONE word might be too obscure. You know what that word was? “Madder,” as a color. From this answer, I bet you can guess my response, which was STET. If readers want to know what that color is, they can look it up.

It’s a mystery how readers are supposed to ever expand their vocabularies if authors restrict themselves to only common words. Don’t do it. Use all the words.