The indubitable definition most commonly understood is something that is so evident that there can be no doubt about it. An example would be the earth revolving around the sun; there is no longer any question that it does. Read on to learn more about this word’s meanings, origins, uses, and synonyms.
Related:
- Faux Pas Meaning: What Does It Mean?
- Kudos Meaning: What Does It Mean?
- Albeit Meaning: What Is It and How to Use?
What Is Indubitable?

If something is indubitable, its existence or truth is beyond any question. The prefix -in means not, and the word dubitable means “capable of being doubted.” Thus, the adjective indubitable means literally “not doubtable.”
Like so many other English words, the origins of indubitable go back to Latin. In this case, the source word was indubitabilis, and it meant the same thing. The word we see and use today came into being with late Middle English.
Examples:
- You can argue that the world is flat, but everyone else considers it indubitable that it isn’t.
- Most scientists think climate change is indubitable, but there are still skeptics out there.
- The video showing the suspect breaking into the store makes it pretty indubitable that he’s the one who robbed it.
- There once were competing theories about what killed the dinosaurs, but now it’s almost indubitable that it was an asteroid.
- The new archeological find makes it indubitable that this land was inhabited long before we thought it was.
- It’s an indubitable fact that you won’t see saber-toothed tigers or woolly mammoths nowadays because they are already extinct.
- Indubitable truths are hard to accept, but they are factual.
Synonyms of Indubitable
Any good writing teacher will tell you that repetition, unless it’s for a certain effect, makes writing dull. That’s why it’s handy to know plenty of synonyms. Fortunately, there are many matches for the indubitable definition, and they can add both variety and spice to your writing. Plus, indubitable is a little unwieldy to say, which might be why you see it more than you hear it.
Just some examples:
- Unquestionable: This is identical to indubitable. The subject is beyond any serious questions as to its veracity.
- Indisputable: If you dispute something, you challenge it or argue against it. Something that’s indisputable can’t be reasonably challenged or argued against.
- Inarguable: This means “not arguable.” It can substitute for indubitable, but there’s another context. That would be if established rules or laws close off arguments against them.
- Incontestable: You might encounter this word in a legal setting since cases often contest (challenge) laws, regulations, or criminal charges.
- Irrefutable: To refute is to deny or to offer a rebuttal to another party’s position or allegation. When you have no sensible counterargument, the other side’s position is irrefutable.
How To Use Indubitable?
Since indubitable is an adjective, it has to describe something. Usually, that something will be an idea or a point of view backed up by solid evidence.
We provided some examples earlier, but here’s another so you don’t have to scroll back:
- It’s an indubitable fact that most of the world’s glaciers have receded over the past several decades, whatever the cause. Then-and-now photographs leave no doubt.
Is It Indubitably or Indubitable?
Since both are real words, the answer is that both work. The key distinction is that indubitably is an adverb, and indubitable is an adjective. Indubitably has to modify an adjective, another adverb, or a verb.
Here’s an example of how to use indubitably correctly:
- With rock-solid evidence, the prosecutor indubitably made the case that the defendant was guilty. The jury really had no choice but to convict.
Final Thoughts
The most widely understood indubitable definition refers to something being so obvious or proven that there’s no questioning it. Common sense, science, or lived experience can determine that. Before you use our word of the day, do some research to make sure that what you’re claiming is beyond dispute!





