If some one says ‘I literally jumped a mile’ but they really mean ‘I figuratively jumped a mile’ it doesn’t work?
Inflammable means flammable?! What a country!
Damn! Beat me to it, and explained it better than I would have. tips hat Nicely done.
Your example is different though—the word’s usage is just wrong. Perhaps the usage is evolving to the point where it will soon have completely flipped meaning, but it still retains its original meaning for most people.
You still frequently hear things like, “I laughed so hard that I peed my pants! Well, not literally.”
The person in your example is simply an idiot. 
(Sadly, given enough time, idiots make usage…)
My favorite flip: Fast. It used to mean immovable. Now it means to move at great speed. “Hold fast!” is the last vestige of it, but it’s kind of only used anchronistically; “fasten” or “fastener”, though, still survive with original meaning.
They don’t, though - they mean, “I jumped a fucking mile”. While that is a figurative use, they’re not using the word ‘literally’ because they want everyone to know that they’re speaking figuratively.
What we really need is an UN-flammable. That would make the distinction clearer. (“Uninflammable” doesn’t really sound right… but then, I can imagine “Uninflatable” existing, so maybe it’s got promise.)
Just running with the notion of “a complete 180”, how about revolution? It’s a complicated story, but one rather well mapped out.
In classical and medieval times, it was essentially a technical term in astronomy meaning a rotation through 360 degrees. Hence Copernicus’s De Revolutionibus. Then, in England in the 17th century, the term gets attached to major political events. But part of that sense is that the likes of the Glorious Revolution are events returning the polity to a previously existing state. But the fact that such events are also seen as unprecidented eventually bleeds into the sense that a “revolution” is an overturning of the prevailing state of affairs. The 360 degrees rotation sense becomes a 180 degrees upheaval one.
By the 20th century, the overturning/upheaval/“complete 180” meaning had become the default, with no implication of anything returning to anything.
I have heard literally 
tons of people use the word literally when they are speaking figuratively.
They’re not using it to MEAN figuratively, though.
They’re using it WRONG, but as a simple intensifier, not to mean the opposite of what it really means.
To say “literally” when they mean exactly the opposite of literally, ie it didn’t really happen they’re just saying it that way to make a point, then it is the opposite.
It’s such a common error that some commie traitor dictionaries are including that usage, so I think it falls under the OP’s reequest.
Moot. It used to mean something worth arguing about.
Still does. In most law schools, students do moots - that is, a learning exercise of arguing a debatable point of law. The profs who set the moot always choose a topic that is not clear cut, to give both sides something to advance in their favour, while responding to the arguments advanced by the other side.
“Moot” has another meaning, of course - that because of a more recent development, the point raised by litigation need not be decided, as the case has become moot. However, that does not necessarily mean the point in issue has been settled, but rather, that because of a factual development, or a related development in the law, the court declines to deal with that particular case.
The word “flammable” goes back to 1805-1815 or so. I don’t think it was created by “safety folks.” I can’t figure out if it was of American origin, the US was an incredibly new country at the time, although it is true that it really took off there.
The original meaning of “bemused” was “confused”. Now, presumably because it sounds so similar, many people use it to mean “amused”. Not exactly the opposite, but quite a difference.
The classic example is the story (probably apocryphal) that, when she saw Christopher Wren’s rebuilt version of St. Paul’s Cathedral, Queen Anne said it as “awful, artificial, and amusing.” The words were all meant as complements – “awe-inspiring,” “artistic,” and “riveting.”
We have it in a way, but it’s NON-flammable.
The bomb: I remember this one as it happened ~1988. In verb, infinitive, or gerund form, it means something bad or getting bad. Suddenly, the noun form meant the best or something very good, e.g. The blueberry pie is the bomb.
Diva: used to mean an expert singer, now it means a spoiled brat.
becoming a tenor: literally means to go to Juliard or something and studying how to sing, but now it means to get hit in the testicles or get your testicles cut off.
Good one. I don’t hear/see it often enough for it to come to the top of my mind.
Maybe the language is evolving to a gradation of “-musement”:
Amusement = quite funny
Bemusement = sort of funny
Cemusement = only of average funniness
Demusement = not especially funny
Efmusement = unfunny