Just recently I was in a conversation with a number of UK mainlanders and we had a debate over what “tories” meant, apparently disproportionately ordinarily it refers to a political party and it’s not usual to use it as short for “territories” as I’ve used it (according to how the debate ended, it was half and half between them). And once again I’m reminded of how people feel to look back at their usage of a word/phrase over the years and cringe.
More tragically, me and a friend were embarrassed once upon realizing everyone was confusing “encephalitis” with “hydrocephalus” when talking to someone about their kid with hydrocephalus. Awkward because encephalitis is caused by HIV.
That’s cool! I’ve never heard of a contronym before.
However the difference is that most of those have different usages - e.g. if you say “I’m going to clip the hedges” vs “I’m going to clip something to the hedges”, you have to use the word differently. With “dust”, it’s different based on the context, because you need to be talking about some sort of powder to be talking about putting something on. If I said “I’m going to dust the furniture”, you would assume I meant clean, but if I said “dust the furniture with cleaning powder”, you’d probably understand the difference. Different locations and activities also help here (e.g. skiing, cake decorating, cleaning, etc).
Nonplussed on the other hand likely derives its alternate meaning from an incorrect understanding of the original meaning, and so it’s used in the exact same manner and context to mean the exact inverse. If I say the sentence “he was nonplussed at the news”, which meaning am I referring to?
“Table” is another contronym that’s ACTUALLY confusing (learned that one from this post as well).