Words one can get confused

This has changed completely during my lifetime. When I was young, flammable didn’t exist and inflammable meant able to be inflamed. Uninflammable meant unable to be inflamed. Trouble was that too many people thought that the in part meant not, as in, say, incapable. So they (who are the they, I wonder) decided to replace the terms with the perfectly understandable flammable and non-flammable. For this reason inflammable ought to avoided like the plague. Although I am most negative on random language change (e.g. the disinterested to mean uninterested), I completely agree with this one.

This may not fit the OP’s description, but I always get tounge twisted on the following:

conscious, conscientious, concise

sympathy, symphony

Rouge: a red powder or cream used as a cosmetic for coloring the cheeks or lips

Rogue: a dishonest or unprincipled man.

Aw, geez! An expression of dismay.

Rick and Morty Season 3 - "Aw Jeez!" - YouTube

Orgies. Social events that may lead your neighbors to say “Aw, geez!”

🎥 CALIGULA (1979) | Trailer | Full HD | 1080p - YouTube
(SFW trailer)

The ruthless leaders of the Grammar Nazis were known as Fewerers.

I saw something funny online related to this once:

If you bite it and you die; it’s poisonous
If it bites you and you die; it’s venomous

What if it bites me and it dies?

That means you’re poisonous

What if it bites itself and I die?

That’s voodoo

What if it bites me and someone else dies?

That’s correlation, not causation

What if we bite each other and neither of us die?

That’s kinky

When I used to play World of Warcraft, rogues were often the subject of posts on the game’s forums complaining that they were overpowered. One time someone posted a thread complaining that rouges were overpowdered. A lot of people missed the joke but still took time to correct the spelling of “rogue.”

I think you need a final punchline question where the answer is “Bite me!”

Decimate hasn’t meant that since about 176 CE. Or thereabouts

The word has been used (loosely and unetymologically, to the irritation of pedants) since 1660s for “destroy a large but indefinite number of.”

[David Attenborough voice] Now nearing extinction, the Lesser Flamingo has been renamed the Fewer Flamingo [/David Attenborough voice]

I do NOT care. That’s how I learned it in school and I am willing to die on this hill!!! Now get off my lawn!!!

But that’s only because you’re under the misguided illusion that we’ll leave the other 9 of you alive on the hill.

@JaneDoe42; speaking of hills,

Calvary: The hill near Jerusalem on which Jesus was crucified.
Cavalry: Soldiers who fight on horseback.

I hear and read folks mixing these two up constantly, it gives me a chuckle every time they do.

I think countable nouns vs uncountable nouns is the usual terminology. But there are so many. If there were less countable nouns, less people would make this elementary mistake.

entomology: the branch of zoology concerned with the study of insects.

etymology: the history of a word or phrase shown by tracing its development and relationships

I got corrected here on this one several years ago.

I knew what ingenious meant, so when I heard/saw “disingenuous” I assumed it had been coined by simply a adding a prefix onto the other word, hence “disingenious” (sic). My excuse is that nobody ever uses ingenuous or even genuous, and may even pronounce it with the i vs. the u (tho I subsequently discovered ingenue, an innocent naive waif, and immediately connected the dots).

Spiders are insects: the entomological fallacy.

needscoffee’s law: If you think you’re using whom correctly, you’re probably not.

Mischievous vs. mischievious

Mischievous is proper. Mischievious is considered to be a misspelling or at least improper form. It shouldn’t be used, but I hear it quite often.

Faze and phase:

Faze: To disturb the composure of
Phase: A particular stage of a process

I very commonly see “That doesn’t phase me,” even on this message board. I’m always tempted to comment “Are we in Star Trek?” It should be “faze” in that sentence.

Pallet/Palate/Palette - very often are mixed up.

Led/Lead - surprisingly, misused on this site a lot. (Using lead instead of led. )

Comprises/composed of - difficult to keep straight.

How about this formulation of needscoffee’s law:

Whomever thinks they are using whom correctly is probably not.