"Flammable" Versus "Inflammable"

Learn right choice in this and other tricky situations.

Mignon Fogarty
4-minute read
Episode #158

Today I'm going to cover two short topics.

So while I was home sick and listening to Undead and Unappreciated and Undead and Unpopular I had two happy little surprises when the main character asked the kind of questions that you listeners ask me. So to thank her for getting me through my cold, I'm going to answer those questions now. Here's the first one from Betsy, the main character in Undead and Unappreciated:

Falling Outs Versus Fallings Out

[Audio Clip]

We can't let him live.

Sure we can.

Majesty, be reasonable. I know you are...were fond of the child. But he is a dangerous child.

I still consider him a friend, OK.

Friends have falling outs. Or would that be fallings out?

Poor Betsy, not only is she under pressure to kill her friend but also baffled by a question with no good answer.

Dictionary.com and Merriam-Webster Online both show "fallings out" as the first plural option, but also show "falling outs" as a second option. When you're looking up something like that in a dictionary, the first option is supposed to be the preferred form. But the problem is that a different dictionary, YourDictionary.com based on Webster's New World College Dictionary, shows the plural options in the reverse order.

A Google search shows that "fallings out" is the more common form on the Internet, but not by much, and neither plural is used very often. There were only about 3,000 incidences of "fallings out" and only about 2,100 instances of "falling outs." Could it mean that most people have no more than one falling out? That would be nice.

I bet the author had Betsy express her uncertainty about how to make "falling out" plural because she'd looked it up couldn't find a good answer.

We have phrasal verbs (covered in episode 114) such as "throw up" and "make out" that are made up of a verb followed by a preposition, but as far as I can tell nouns that are made up of a verb followed by a preposition aren't called phrasal nouns; they're just considered compound words. I think they should be called phrasal nouns, but I bet I won't win that battle.

Anyway, I tried to think of other compound words that end in prepositions besides "falling out" to see how they're made plural. Two I came up with are "push-up" and "holdout." I can barely do one push-up, but I bet my husband could do 50 push-ups. "Push-ups" with the "s" after the "up" is clearly the preferred plural. I've never heard anyone ask, "How many pushes-up can you do?"

The same is true for "holdout." I'd ask "How many holdouts are there who think it's not OK to split infinitives?" The "s" goes at the end.

So I've decided that if I ever need to make "falling-out" plural, I will go with "falling-outs." "Geez, how many falling-outs did you guys have?" My reasoning isn't bulletproof, so don't take it as law, but it's simple and in the absence of a definitive answer from dictionaries, I think it makes sense.

Flammable Versus Inflammableflammable

Here's Betsy's second conundrum from Undead and Unpopular.

Someone's at the door. I said wiping off my face.

Oh, there is not.

Jessica, there totally is.

You know, you're like one of those annoying, yappy little dogs. Every time a car rolls by outside, you freak out and decide someone is coming up the walk.

Bong, bong.

I hate you, she sighed, getting up.

I checked my watch. It was almost 6 o'clock in the morning. Probably not a vampire. They didn't like to be running around so close to sunrise. As a rule, they were more flammable than gasoline. Or was it inflammable? I always got those two mixed up. My D in chemistry had never served me well.

Again, Betsy is confused with good reason:"Flammable" and "inflammable" mean the same thing; they both mean "easy to burn." "Inflammable" is the original word, but then in the 1920s, according to Merriam-Webster's Dictionary of English Usage, the National Fire Protection Association started encouraging people to use the word "flammable" instead because they were worried people could mistakenly think "inflammable" meant "not flammable." They saw it as a safety issue. Academics were inflamed (get it?) because they didn't appreciate the Fire Protection Association messing with the language and promoting "corrupt" words. Perhaps they thought dumb people should die a firey death if they went around holding matches to inflammable objects. Regardless, linguists have groused about "flammable" in usage books ever since.

If safety is important and you really want people to understand that the thing you're talking about could burst into flames, it's best to use "flammable" or some other phrase like "burns easily." In other cases, you can use whichever word you like.


I'm excited to be able to tell you that the audiobook version of my book, Grammar Girl's Quick and Dirty Tips for Better Writing, was just nominated for an Audie award. That's like the Oscar of audiobooks, but I have a feeling the after-parties aren't as good.

Finally, I've been getting great feedback on my free weekly e-mail newsletter. People say they love getting a tip by e-mail, so if you haven't signed up yet, be sure to do it today.

That's all. Thanks for listening.

Web Bonus

I found myself wondering if the nature of the compound made a difference in how the nouns should be made plural.

  • "Falling-out" tended to be hyphenated in dictionaries.
  • "Push-up" was hyphenated in every dictionary I checked.
  • "Holdout" was a closed compound ("holdout") at M-W.com and Dictionary.com, but the OED showed it as both a closed compound and a hyphenated compound.
It doesn't appear that the form of the compound plays a role in how a word is made plural, at least in the three examples I checked.

About the Author

Mignon Fogarty

Mignon Fogarty is the founder of Quick and Dirty Tips and the author of seven books on language, including the New York Times bestseller "Grammar Girl's Quick and Dirty Tips for Better Writing." She is an inductee in the Podcasting Hall of Fame, and the show is a five-time winner of Best Education Podcast in the Podcast Awards. She has appeared as a guest expert on the Oprah Winfrey Show and the Today Show. Her popular LinkedIn Learning courses help people write better to communicate better.